Abstract. Objectives. Three-dimensional visualisation of sonographic callus has the potential to improve the accuracy and accessibility of ultrasound evaluation of fracture healing. The aim of this study was to establish a reliable method for producing three-dimensional reconstruction of sonographic callus. Methods. A prospective cohort of ten patients with a closed tibial shaft fracture managed with intramedullary nailing were recruited and underwent ultrasound scanning at 2-, 6- and 12-weeks post-surgery. Ultrasound B-mode capture was performed using infrared tracking technology to map each image to a three-dimensional lattice. Using echo intensity, semi-automated mapping was performed by two independent reviewers to produce an anatomic three-dimensional representation of the fracture. Agreement on the presence of sonographic bridging callus on three-dimensional reconstructions was assessed using the kappa coefficient. Results. Nine of the ten patients achieved union at six months. At six weeks, seven patients had bridging callus at ≥1 cortex on the three-dimensional reconstruction; when present all united. Compared to radiographs, no bridging callus was present in any patient. Of the three patients lacking sonographic bridging callus, one went onto a nonunion (77.8%-sensitive and 100%-specific to predict union). At twelve weeks, nine patients had bridging callus at ≥1 cortex on three-dimensional reconstruction and all united (100%-sensitive and 100%-specific to predict union). Compared to radiographs, seven of the nine patients that united had bridging callus. Three-dimensional reconstruction of the anteromedial and anterolateral tibial surface was achieved in all patients, and detection of sonographic bridging callus on the three-dimensional reconstruction demonstrated substantial inter-observer agreement (kappa=0.78, 95% confidence interval 0.29–1.0, p=0.011). Conclusions. Three-dimensional fracture reconstruction can be created using multiple ultrasound images in order to evaluate the presence of bridging callus. This imaging modality has the potential to identify impaired healing at an early stage in fracture management. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Background. There is no consensus on which glenoid plane should be used in total shoulder arthroplasty. Nevertheless, anatomical reconstruction of this plane is imperative for the success of a total shoulder arthroplasty. Methods. Three-dimensional reconstruction CT-scans were performed on 152 healthy shoulders. Four different glenoid planes, each determined by three surgical accessible bony reference points, are determined. The first two are triangular planes, defined by the most anterior and posterior point of the glenoid and respectively the most inferior point for the Saller's Inferior plane and the most superior point for the Saller's Superior plane. The third plane is formed by the best fitting circle of the superior tubercle and the most anterior and posterior point at the distal third of the glenoid (Circular Max). The fourth plane is formed by the best fitting circle of three points at the rim of the inferior quadrants of the glenoid (Circular Inferior). We hypothesized that the plane with normally distributed parameters, narrowest variability and best reproducibility would be the most suitable surgical glenoid plane. Results. No difference in position of the mean humeral center of rotation is found between the Circular Max and Circular Inferior plane (X=91.71degrees/X=91.66degrees p=0.907 and Y=90.83degrees /Y=91.7degrees p=0.054 respectively), while clear deviations are found for the Saller's Inferior and Saller's Superior plane (p < 0.001). The Circular Inferior plane has the lowest variability to the coronal scapular plane (p<0.001). Conclusion. This study provides arguments to use the Circular Inferior glenoid plane as preferred surgical plane of the glenoid. Level of evidence: Level II, Basic Science Study, Anatomical Survey

Three-dimensional (3D) printing has become more frequently used in surgical specialties in recent years. Orthopaedic surgery is particularly well-suited to 3D printing applications, and thus has seen a variety of uses for this technology. These uses include pre-operative planning, patient-specific instrumentation (PSI), and patient-specific implant production. As with any new technology, it is important to assess the clinical impact, if any, of three-dimensional printing. The purpose of this review was to answer the following questions: . What are the current clinical uses of 3D printing in orthopaedic surgery?. Does the use of 3D printing have an effect on peri-operative outcomes?. Four electronic databases (Embase, MEDLINE, PubMed, Web of Science) were searched for Articles discussing clinical applications of 3D printing in orthopaedics up to November 13, 2018. Titles, abstracts, and full texts were screened in duplicate and data was abstracted. Descriptive analysis was performed for all studies. A meta-analysis was performed among eligible studies to compare estimated blood loss (EBL), operative time, and fluoroscopy use between 3D printing cases and controls. Study quality was assessed using the Methodological Index for Non-Randomized Studies (MINORS) criteria for non-randomized studies and the Cochrane Risk of Bias Tool for randomized controlled trials (RCTs). This review was prospectively registered on PROSPERO (Registration ID: CRD42018099144). One-hundred and eight studies were included, published between 2012 and 2018. A total of 2328 patients were included in these studies, and 1558 patients were treated using 3D printing technology. The mean age of patients, where reported, was 47 years old (range 3 to 90). Three-dimensional printing was most commonly reported in trauma (N = 41) and oncology (N = 22). Pre-operative planning was the most common use of 3D printing (N = 63), followed by final implants (N = 32) and PSI (N = 22). Titanium was the most commonly used 3D printing material (16 studies, 27.1%). A wide range of costs were reported for 3D printing applications, ranging from “less than $10” to $20,000. The mean MINORS score for non-randomized studies was 8.3/16 for non-comparative studies (N = 78), and 17.7/24 for non-randomized comparative studies (N = 19). Among RCTs, the most commonly identified sources of bias were for performance and detection biases. Three-dimensional printing resulted in a statistically significant decrease in mean operative time (−15.6 mins, p < .00001), mean EBL (−35.9 mL, p<.00001), and mean fluoroscopy shots (−3.5 shots, p < .00001) in 3D printing patients compared to controls. The uses of 3D printing in orthopaedic surgery are growing rapidly, with its use being most common in trauma and oncology. Pre-operative planning is the most common use of 3D printing in orthopaedics. The use of 3D printing significantly reduces EBL, operative time, and fluoroscopy use compared to controls. Future research is needed to confirm and clarify the magnitude of these effects

Sonographic callus may enable assessment of fracture healing. The aim of this study was to establish a reliable method for three-dimensional reconstruction of sonographic callus. Patients that underwent non-operative management of displaced midshaft clavicle fractures and intramedullary nailing of tibia fractures were prospectively recruited and followed to union. Ultrasound scanning was performed at periodical time points following injury. Infra-red tracking technology was used to map each image to a three-dimensional lattice. Criteria was fist established for two-dimensional bridging callus detection in a pilot study. Using echo intensity of the ultrasound image, semi-automated mapping was used to create an anatomic three-dimensional representation of fracture healing. Agreement on the presence of sonographic bridging callus was assessed using the kappa coefficient and intra-class-correlation (ICC) between observers. 112 clavicle fractures and 10 tibia fractures completed follow-up at six months. Sonographic bridging callus was detected in 62.5% (n=70/112) of the clavicles at six weeks post-injury. If present, union occurred in 98.6% of the fractures (n=69/70). If absent, nonunion developed in 40.5% of cases (n=17/42)(73.4%-sensitive and 100%-specific to predict union). Out of 10 tibia fractures, 7 had bridging callus of at least one cortex at 6 weeks and when present all united. Of the three patients lacking sonographic bridging callus, one went onto a nonunion (77.8%-sensitive and 100%-specific to predict union). The ICC for sonographic callus between four reviewers was 0.82 (95% CI 0.68–0.91). Three-dimensional ultrasound reconstruction of bridging callus has the potential to identify impaired fracture healing at an early stage in fracture management

Total temporomandibular joint (TMJ) replacements reduce pain and improve quality of life in patients suffering from end-stage TMJ disorders, such as osteoarthritis and trauma. Jaw kinematics measurements following TMJ arthroplasty provide a basis for evaluating implant performance and jaw function. The aim of this study is to provide the first measurements of three-dimensional kinematics of the jaw in patients following unilateral and bilateral prosthetic TMJ surgeries. Jaw motion tracking experiments were performed on 7 healthy control participants, 3 unilateral and 1 bilateral TMJ replacement patients. Custom-made mouthpieces were manufactured for each participant's mandibular and maxillary teeth, with each supporting three retroreflective markers anterior to the participant's lip line. Participants performed 15 trials each of maximum jaw opening, lateral and protrusive movements. Marker trajectories were simultaneously measured using an optoelectronic tracking system. Laser scans taken of each dental plate, together with CT scans of each patient, were used to register the plate position to each participant's jaw geometry, allowing 3D condylar motion to be quantified from the marker trajectories. The maximum mouth opening capacity of joint replacement patients was comparable to healthy controls with average incisal inferior translations of 37.5mm, 38.4mm and 33.6mm for the controls, unilateral and bilateral joint replacement patients respectively. During mouth opening the maximum anterior translation of prosthetic condyles was 2.4mm, compared to 10.6mm for controls. Prosthetic condyles had limited anterior motion compared to natural condyles, in unilateral patients this resulted in asymmetric opening and protrusive movements and the capacity to laterally move their jaw towards their pathological side only. For the bilateral patient, protrusive and lateral jaw movement capacity was minimal. Total TMJ replacement surgery facilitates normal mouth opening capacity and lateral and inferior condylar movements but limits anterior condylar motion. This study provides future direction for TMJ implant design

Background. The femoral head center shift on reduction time in total hip arthroplasty (THA) causes alteration of the muscle tension around the hip joint. Many studies about the shift of the femoral head in the cranio-caudal direction or medio-lateral direction on coronal plane have been reported. It has been known widely that the shift on these directions influence tension of the abductor muscle around the hip joint. Nevertheless few studies about the three-dimensional shift including the antero-posterior direction have been reported. Purpose. The purpose of this study is to evaluate the three-dimensional shift of the femoral head center in THA using three-dimensional THA templating software. Subjects & Methods. The subjects of this study were 156 primary THA cases of 143 patients. Using CT-based three-dimensional THA templating software ZedHip® (LEXI, Tokyo Japan), simulation of optimal implantation was performed on each THA case. On case which has over anteverted or less anteverted femoral neck, a stem which has modular neck system was selected to adjust anteversion of the femoral neck. The three-dimensional shift of the femoral head center on reduction time was calculated with ZedHip®. The three-dimensional shift was resolve into cranio-caudal, medio-lateral and antero-posterior direction (Fig. 1). Furthermore the correlation between the amount of the shift and hip joint deformity was investigated. Results. The average amount of the shift on cranio-caudal direction was 9.9mm to caudal side, on medio-lateral direction was 3.1mm to medial side and on antero-posterior direction was 2.6mm to posterior side. The average total amount of three-dimensional shift was 12.9mm (Fig. 2). On Crowe type 1 hips in 88 cases, the average shift to posterior side was 3.2mm, on Crowe type 2 in 20 cases was 3.7mm and on Crowe type 3 in 13 cases was 4.0mm. Among them there was no significant difference (Fig. 3). Conclusion. At THA surgery, the femoral head center shifted three-dimensionally and the maximum amount of shift on antero-posterior direction was 16.6mm to posterior side. There was no correlation between these amounts of the shift on antero-posterior direction and anatomical deformity of the hip joint. It is important to understand the shift of the femoral head center for predicting the alteration of muscle tension around the hip joint. The shift on antero-posterior direction influences the tension of iliopsoas muscle and there is a possibility that the shift to posterior side causes anterior iliopsoas impingement after THA surgery

Abstract. OBJECTIVES. An unresolved challenge in osteoarthritis research is characterising the localised intra-tissue mechanical response of articular cartilage. The aim of this study was to explore whether laboratory micro-computed tomography (micro-CT) and digital volume correlation (DVC) permit non-destructive visualisation of three-dimensional (3D) strain fields in human articular cartilage. METHODS. Human articular cartilage specimens were harvested from the knee (n=4 specimens from 2 doners), mounted into a loading device and imaged in the loaded and unloaded state using a micro-CT scanner. Strain was calculated throughout the volume of the cartilage using the CT image data. RESULTS. Strain was calculated in the 3D volume with a spatial resolution of 75 µm, and the volumetric DVC calculated strain was within 5% of the known applied stain. Variation in strain distribution between the superficial, middle and deep zones was observed, consistent with the different architecture of the material in these locations. CONCLUSIONS. The DVC method is suitable for calculating strain in human articular cartilage. This method will be useful to generate chondral repair scaffolds that that seek to replicate the strain gradient in cartilage. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Objective. In total knee arthroplasty, three-dimensional “criss-cross” line locate femoral osteotomy and conventional osteotomy were used. By comparing the two methods osteotomy in patients before and after surgery and imaging-related information data, to evaluate the recent post operative efficacy, at the same time to find out if there has clinical evidence that three-dimensional “criss-cross” line locate femoral osteotomy can be used in total knee arthroplasty. Methods. From July 2012 to July 2014, 64 patients who undertook the artificial total knee arthroplasty were divided into 2 groups: conventional osteotomy group(group A)and three-dimensional “criss-cross” line locate femoral osteotomy group(group B). In the X-ray of the two groups, it was measured that the hip-knee-ankle angle and the joint gap symmetry of 90°flexion degree. It was also measured that the two group joints range of motion. Those data were statistically analyzed. The KSS score of the two groups were compared. Results. In Group B the excellent and good rate was 93.8%, and Group A was 81.3%. The postoperative results of Group A were relatively better than Group B in limb alignment and joint mobility. There were significant differences between the prosthesis placement of the two group patients. Conclusion. The Short-term results of the three-dimensional “criss-cross” line locate femoral osteotomy group was better than the conventional osteotomy group. The reference osteotomy method of three-dimensional “criss-cross” line is very helpful to have a good result in TKA

We have measured the three-dimensional patterns of carpal deformity in 20 wrists in 20 rheumatoid patients in which the carpal bones were shifted ulnarwards on plain radiography. Three-dimensional bone models of the carpus and radius were created by computerised tomography with the wrist in the neutral position. The location of the centroids and rotational angle of each carpal bone relative to the radius were calculated and compared with those of ten normal wrists. In the radiocarpal joint, the proximal row was flexed and the centroids of all carpal bones translocated in an ulnar, proximal and volar direction with loss of congruity. In the midcarpal joint, the distal row was extended and congruity generally well preserved. These findings may facilitate more positive use of radiocarpal fusion alone for the deformed rheumatoid wrist

We used three-dimensional movement analysis by computer modelling of knee flexion from 0° to 50° in 14 knees in 12 patients with recurrent patellar dislocation and in 15 knees in ten normal control subjects to compare the in vivo three-dimensional movement of the patella. Flexion, tilt and spin of the patella were described in terms of rotation angles from 0°. The location of the patella and the tibial tubercle were evaluated using parameters expressed as percentage patellar shift and percentage tubercle shift. Patellar inclination to the femur was also measured and patellofemoral contact was qualitatively and quantitatively analysed. The patients had greater values of spin from 20° to 50°, while there were no statistically significant differences in flexion and tilt. The patients also had greater percentage patellar shift from 0° to 50°, percentage tubercle shift at 0° and 10° and patellar inclination from 0° to 50° with a smaller oval-shaped contact area from 20° to 50° moving downwards on the lateral facet. Patellar movement analysis using a three-dimensional computer model is useful to clearly demonstrate differences between patients with recurrent dislocation of the patella and normal control subjects

Using roentgen stereophotogrammetry we have recorded the three-dimensional movements of the knee during an anteroposterior laxity test in 36 patients with torn anterior cruciate ligaments and in three cadaver knees. At 30 degrees of knee flexion and before loads were applied the tibia occupied a more laterally rotated position if the anterior cruciate ligament had been injured. When the tibia was pulled anteriorly knees with cruciate deficiency rotated more laterally and were more abducted than normal knees. Posterior traction induced lateral rotation in the injured knee and medial rotation in the intact one. Precise knowledge of the three-dimensional instability of the anterior cruciate deficient knee may be important when the laxity is evaluated only in relation to one of the three cardinal axes

This paper describes how advances in three-dimensional printing may benefit the military trauma patient, both deployed on operations and in the firm base. Use of rapid prototype manufacturing to produce a 3D representation of complex fractures that can be held and rotated will aid surgical planning within multidisciplinary teams. Patient-clinician interaction can also be aided using these graspable models. The education of military surgeons could improve with the subsequent accurate, inexpensive models for anatomy and surgical technique instruction. The developing sphere of additive manufacturing (3D printing functional end-use components) lends itself to further advantages for the military orthopaedic surgeon. Military trauma patients could benefit from advances in direct metal laser sintering which enable the manufacture of complex surfaces and porous structures on bio-metallic implants not possible using conventional manufacturing. “Bio-printing” of tissues mimicking anatomical structures has potential for military trauma patients with bone defects. Deployed surgeons operating on less familiar fracture sites could benefit from three-dimensionally printing patient-specific medical devices. These can make operating technically easier, reducing radiation exposure and operating time. Further ahead, it may be possible to contemporaneously 3D print medical devices unavailable from the logistics chain whilst operating in the deployed environment

We report the case of a 12-year-old boy with flexion loss in the left elbow caused by deficient of the concavity corresponding to the coronoid fossa in the distal humerus. The range of motion (ROM) was 15°/100°, and pain was induced by passive terminal flexion. Plain radiographs revealed complete epiphyseal closure, and computed tomography (CT) revealed a flat anterior surface of the distal humerus; the coronoid fossa was absent. Then, the bony morphometric contour was surgically recreated using a navigation system and a three-dimensional elbow joint model. A three-dimensional model of the elbow joint was made preoperatively and the model comprising the distal humerus was milled so that elbow flexion flexion of more than 140° could be achieved against the proximal ulna and radius. Navigation-assisted surgery (contouring arthroplasty) was performed using CT data from this milled three-dimensional model. Subsequently, an intraoperative passive elbow flexion of 135° was obtained. However, active elbow flexion was still inadequate one year after operation, and a triceps lengthening procedure was performed. At the final follow-up one year after triceps lengthening, a considerable improvement in flexion was observed with a ROM of −12°/125°. Plain radiographs revealed no signs of degenerative change, and CT revealed the formation of the radial and coronoid fossae on the anterior surface of the distal humerus. Navigation-assisted surgery for deformity of the distal humerus based on a contoured three-dimensional model is extremely effective as it facilitates evaluation of the bony morphometry of the distal humerus. It is particularly useful as an indicator for milling the actual bone when a model of the mirror image of the unaffected side cannot be applied to the affected side as observed in our case

Purpose: Scoliosis is a three-dimensional deformation of the spinal column. Modern surgical techniques have attempted to address this 3D component of the problem but pre- and postoperative measurements lack precision. A solution is stereoradiographic 3D reconstruction providing 1.1 mm precision for vertebral shape and 1.4° precision for axial rotation. Material and methods: Ten patients (seven adolescents and three adults) with idiopathic scoliosis (mean 56°, range 36°–78°) were treated with an in situ arching method. A calibrated teleradiogram (AP and lateral view) was obtained before and after surgery. The spinal columns were reconstructed by stereoradiography. Six rotation angles were measured in the three planes for each vertebra and each intervertebral space, taking into account the curvatures and their apical and junctional zones. Results: Preoperatively, for thoracic scoliosis, measurements were: mean vertebral axial rotation (VAR) measured at the apex = 20°; mean lateral axial rotation (LAR) of the junctional zones = 30°; mean intervertebral rotation (IVR) = 10°. Depending on the curvatures, in situ arching yielded a 52–60% correction of the VAR at the apex, and 78–79% correction of the junctional zones. VLR of the junctional zoenes was improved 58–74%. Intervertebral sagittal rotation (ISR) at the summit (kyphosis) was improved 5.5° on the average. Discussion: Unlike computed tomoraphy where scans are obtained in the supine position, three-dimensional reconstruction of the spinal column enables a precise analysis of the loaded spine. Improvement was significant in the frontal plane with 18.3° and 21.4° improvement of the VLR for the thoracic and thoracolumbar junctional zones respectively, compared with the rod rotation where the peroperative stereophotogram showed a 9.6° and 8.6° gain respectively. There was a real improvement in VAR, differing from the literature where the rotation of the rod appears to be less pronounced. Conclusion: Three-dimensional reconstruction of the spinal column enables a segmentary analysis of scoliosis deformations. In addition, by enabling a view of the spinal column in all directions, angle measurements can be made with precision allowing repeated measurements and comparisons. This technique demonstrated the efficacy of in situ arching in improving vertebral rotation

Summary Statement. We used three-dimensional software to assess different anatomic variables in the femur. The canal of Femur twisted slightly below the lesser trochanter in cases with a larger angle of anteversion. Introduction. Accurate positioning of the joint prosthesis is essential for successful total hip arthroplasty (THA). To aid in tailoring of the prosthesis, we used three-dimensional software to assess different anatomic variables in the femur. Patients & Methods. We used CT imaging data of the unaffected normal side of the 25 patients (22 females, age range 30 to 81 years) who underwent THA in 2012 in our hospital. The femur was reconstructed from CT data and measured using three-dimensional modeling software (Mimics 16.0 Materialise, Leuven, Belgium). We measured ellipse fitting to the medullary canal in the axial plane of the femur at 20-mm intervals. The angle between the major axis of those ellipses and the axis of the femoral neck was measured and expressed as the canal rotation. The distance between the lesser trochanter and the center of the femoral head was measured along the Z axis. Results. The major axes of the ellipses direct to medial, front and medial side in the level of epiphysis, above isthmus and distal portion respectively in all cases. The maximum rotated level was above isthmus. The rotation angle in the proximal portion ranged from 36 to 84 degrees (mean, 60.6 degrees, SD ± 12.1). The rotation angle of the distal portion ranged from 71 to 95 degrees (mean, 86.1 degrees, SD ± 6.1). Discussion/Conclusion. The torsion of the canal varied more widely between individuals in the proximal portion than did the distal portion. In addition, the torsion of the proximal aspect, although more variable, was on average smaller when the angle of anteversion was large. Because the canal twisted slightly below the lesser trochanter in cases with a larger angle of anteversion, it is suggested that attention to the degree of anteversion of a flat prosthesis stem is warranted

We evaluated the impact of stereo-visualisation of three-dimensional volume-rendering CT datasets on the inter- and intraobserver reliability assessed by kappa values on the AO/OTA and Neer classifications in the assessment of proximal humeral fractures. Four independent observers classified 40 fractures according to the AO/OTA and Neer classifications using plain radiographs, two-dimensional CT scans and with stereo-visualised three-dimensional volume-rendering reconstructions. Both classification systems showed moderate interobserver reliability with plain radiographs and two-dimensional CT scans. Three-dimensional volume-rendered CT scans improved the interobserver reliability of both systems to good. Intraobserver reliability was moderate for both classifications when assessed by plain radiographs. Stereo visualisation of three-dimensional volume rendering improved intraobserver reliability to good for the AO/OTA method and to excellent for the Neer classification. These data support our opinion that stereo visualisation of three-dimensional volume-rendering datasets is of value when analysing and classifying complex fractures of the proximal humerus

We have studied the three-dimensional geometry of the proximal humerus on human cadaver specimens using a digitised measuring device linked to a computer. Our findings demonstrated the variable shape of the proximal humerus as well as its variable dimensions. The articular surface, which is part of a sphere varies individually in its orientation as regards inclination and retroversion, and it has variable medial and posterior offsets. These variations cannot be accommodated by the designs of most contemporary humeral components. Although good clinical results can be achieved with current modular and non-modular components their relatively fixed geometry prevents truly anatomical restoration in many cases. To try to restore the original three-dimensional geometry of the proximal humerus, we have developed a new type of humeral component which is modular and adaptable to the individual anatomy. Such adaptability allows correct positioning of the prosthetic head in relation to an individual anatomical neck, after removal of the marginal osteophytes. The design of this third-generation prosthesis respects the four geometrical variations which have been demonstrated in the present study. These are inclination, retroversion, medial offset and posterior offset

We created virtual three-dimensional reconstruction models from computed tomography scans obtained from patients with acetabular fractures. Virtual cylindrical implants were placed intraosseously in the anterior column, the posterior column and across the dome of the acetabulum. The maximum diameter which was entirely contained within the bone was determined for each position of the screw. In the same model, the cross-sectional diameters of the columns were measured and compared to the maximum diameter of the corresponding virtual implant. We found that the mean maximum diameter of virtual implant accommodated by the anterior columns was 6.4 mm and that the smallest diameter of the columns was larger than the maximum diameter of the equivalent virtual implant. This study suggests that the size of the screw used for percutaneous fixation of acetabular fractures should not be based solely on the measurement of cross-sectional diameter and that virtual three-dimensional reconstructions might be useful in pre-operative planning

We investigated the three-dimensional morphological differences of the articular surface of the femoral trochlea in patients with recurrent dislocation of the patella and a normal control group using three-dimensional computer models. There were 12 patients (12 knees) and ten control subjects (ten knees). Three-dimensional computer models of the femur, including the articular cartilage, were created. Evaluation was performed on the shape of the articular surface, focused on its convexity, and the proximal and mediolateral distribution of the articular cartilage of the femoral trochlea. The extent of any convexity, and the proximal distribution of the articular cartilage, expressed as the height, were shown by the angles about the transepicondylar axis. The mediolateral distribution of the articular cartilage was assessed by the location of the medial and lateral borders of the articular cartilage. The mean extent of convexity was 24.9° . sd. 6.7° for patients and 11.9° . sd. 3.6° for the control group (p < 0.001). The mean height of the articular cartilage was 91.3° . sd. 8.3° for the patients and 83.3° . sd. 7.7° for the control group (p = 0.03), suggesting a wider convex trochlea in the patients with recurrent dislocation of the patella caused by the proximally-extended convex area. The lateral border of the articular cartilage of the trochlea in the patients was more laterally located than in the control group. Our findings therefore quantitatively demonstrated differences in the shape and distribution of the articular cartilage on the femoral trochlea between patients with dislocation of the patella and normal subjects

The three-dimensional architecture of bovine articular cartilage collagen and its relationship to split lines has been studied with scanning electron microscopy. In the middle and superficial zones, collagen was organised in a layered or leaf-like manner. The orientation was vertical in the intermediate zone, curving to become horizontal and parallel to the articular surface in the superficial zone. Each leaf consisted of a fine network of collagen fibrils. Adjacent leaves merged or were closely linked by bridging fibrils and were arranged according to the split-line pattern. The surface layer (lamina splendens) was morphologically distinct. Although ordered, the overall collagen structure was different in each plane (anisotropic) a property described in previous morphological and biophysical studies. As all components of the articular cartilage matrix interact closely, the three-dimensional organisation of collagen is important when considering cartilage function and the processes of cartilage growth, injury and repair

Introduction. Kinematically or anatomically aligned total knee arthroplasty (TKA) has been reported to provide improved clinical outcomes by replicating patient's original joint line [1][2]. It has been known that tibial (joint line) varus varies among patients, and the tibial varus would increase over progression of arthritis and bone remodeling. For those patients with significant deformity, the current tibial varus may significantly differ from its pre-diseased state. In this exploratory study, geometry and alignment of the tibial growth plate were measured with respect to tibial anatomical landmarks in order to better understand modes of tibial deformity and seek possible application in reconstructing pre-diseased joint alignment. Methods. CT scans of sixteen healthy Japanese knees (M6:F10, Age 31.9±13.9 years) were studied. Three-dimensional reconstruction models were created using Mimics 17 (Materialise, Leuven, Belgium). First, a mid-sagittal tibial reference plane, for comparing the varus/valgus orientation of the tibial plateau to that of the growth plate, was defined by the medial margin of the tibial tuberosity, origin of the PCL and center of the foot joint. The tibial plateau (or joint line plane) was determined from three points; dwell point of femur (aligned in extension) on lateral tibial articular surface, and two points at anterior and posterior rim of medial tibial articular surface sampled in the sagittal view and coinciding with dwell point of femur on medial tibia. Then, a three-dimensional model of the tibial growth plate was extracted using the Livewire function and mask editing tools in Mimics. To determine 3D orientation of the growth plate (GP), the vertical mass moment of inertia axis was calculated for the 3D model. The inertia axes were also determined for medial and lateral half of the GP (Figure 1). Results. Tibial plateau (TP) had 2.39±1.72 degrees of varus in coronal view and 11.12±3.90 degrees of posterior inclination in sagittal view. The shape of the GP is noticeably different between medial and lateral. The medial half tends to incline posteriorly towards medial, while the lateral half is twisted anteriorly. In coronal view, GP axis was in 1.27±1.49 degrees valgus to midsagittal plane. Normal axis of the TP was in varus to the GP axis by 3.66±1.79 degrees. The GP medial half was in 5.81±2.49 degrees valgus and 1.63±2.59 degrees anteriorly inclined with respect to the TP. The GP lateral half was in 11.65±2.07 degrees varus and 18.66±4.44 degrees anteriorly inclined relative to the TP. Discussion. The preliminary results from 16 healthy knees suggested that the tibial growth plate is aligned to midsagittal plane and tibial plateau in varus/valgus orientations with relatively small variations. More study samples will be required to validate usefulness of this method in surgical planning. Distinctive shape difference for medial and lateral half of the growth plate was also observed. Future study should also include diseased knees with various levels of deformities

Glenoid and humeral head bone defects have long been recognized as major determinants in recurrent shoulder instability as well as main predictors of outcomes after surgical stabilization. However, a universally accepted method to quantify them is not available yet. The purpose of the present study is to describe a new CT method to quantify bipolar bone defects volume on a virtually generated 3D model and to evaluate its reproducibility.

A cross-sectional observational study has been conducted. Forty CT scans of both shoulders were randomly selected from a series of exams previously acquired on patients affected by anterior shoulder instability. Inclusion criterion was unilateral anterior shoulder instability with at least one episode of dislocation. Exclusion criteria were: bilateral shoulder instability; posterior or multidirectional instability, previous fractures and/or surgery to both shoulders; congenital or acquired inflammatory, neurological, or degenerative diseases. For all patients, CT exams of both shoulders were acquired at the same time following a standardized imaging protocol. The CT data sets were analysed on a standard desktop PC using the software 3D Slicer. Computer-based reconstruction of the Hill-Sachs and glenoid bone defect were performed through Boolean subtraction of the affected side from the contralateral one, resulting in a virtually generated bone fragment accurately fitting the defect. The volume of the bone fragments was then calculated. All measurements were conducted by two fellowship-trained orthopaedic shoulder surgeons. Each measurement was performed twice by one observer to assess intra-observer reliability. Inter and intra-observer reliability were calculated. Intraclass Correlation Coefficients (ICC) were calculated using a two-way random effect model and evaluation of absolute agreement. Confidence intervals (CI) were calculated at 95% confidence level for reliability coefficients. Reliability values range from 0 (no agreement) to 1 (maximum agreement).

The study included 34 males and 6 females. Mean age (+ SD) of patients was 36.7 + 10.10 years (range: 25 – 73 years). A bipolar bone defect was observed in all cases. Reliability of humeral head bone fragment measurements showed excellent intra-observer agreement (ICC: 0.92, CI 95%: 0.85 – 0.96) and very good interobserver agreement (ICC: 0.89, CI 95%: 0.80 – 0.94). Similarly, glenoid bone loss measurement resulted in excellent intra-observer reliability (ICC: 0.92, CI 95%: 0.85 – 0.96) and very good inter-observer agreement (ICC: 0.84, CI 95%:0.72 – 0.91).

In conclusion, matching affected and intact contralateral humeral head and glenoid by reconstruction on a computer-based virtual model allows identification of bipolar bone defects and enables quantitative determination of bone loss.

The three-dimensional (3D) correction of glenoid erosion is critical to the long-term success of total shoulder replacement (TSR). In order to characterise the 3D morphology of eroded glenoid surfaces, we looked for a set of morphological parameters useful for TSR planning. We defined a scapular coordinates system based on non-eroded bony landmarks. The maximum glenoid version was measured and specified in 3D by its orientation angle. Medialisation was considered relative to the spino-glenoid notch. We analysed regular CT scans of 19 normal (N) and 86 osteoarthritic (OA) scapulae. When the maximum version of OA shoulders was higher than 10°, the orientation was not only posterior, but extended in postero-superior (35%), postero-inferior (6%) and anterior sectors (4%). The medialisation of the glenoid was higher in OA than normal shoulders. The orientation angle of maximum version appeared as a critical parameter to specify the glenoid shape in 3D. It will be very useful in planning the best position for the glenoid in TSR. Cite this article: Bone Joint J 2014;96-B:513–18

Introduction:. For 30 years, uncemented anatomic hip stems have been implanted with documented clinical results[1,2]. Their geometry can be linked back to the geometry of the PCA and ABG stems. Modifications to date include stem length, body geometry, material, and reduction in distal geometry. New tools have been developed allowing anatomical measurements and analysis of three-dimensional digital femora geometry through CT scans[3]. The purpose of this study is to analyze three-dimensional contact of various anatomic hip stem designs using this technique. Methods:. Six femora (57–87 yrs, 72–88 kg), were selected from a CT scan database (SOMA™) of 604 Caucasian bones. They were selected based on femoral anteversion (average +/−1.5 * std. dev.) with three measuring[4] 8–10° and three 31–33° of anteversion. The CT scans were segmented into cancellous/cortical bone and converted into CAD models in PRO/Engineer Wildfire (v.5). A/P views of the bones were scaled to a 120% magnification to allow three surgeons to surgically template and choose the stem size and location (maximizing fill (n = 1); restoring the head center (n = 2)) with two implant designs (1-Citation TMZF and 2-ABG II Monolithic, Stryker Orthopaedics, Mahwah). Measurements from templating were used to virtually implant CAD models of the implants into the bones (n = 36 bone/stem assemblies). The assemblies were imported into Geomagic Qualify 2012 for 3D deviation analysis comparing the coated region of the implant to the cortical-cancellous boundary. The analysis generated color map profiles based on the following categories: Contact (−2.0 to 0.5 mm), Conformity (0.5 to 2.0 mm), Proximity (2.0 to 5.0 mm), and Gap (5.0 to 12 mm) and the percent of the surface that was within each of these categories. These results were compared for patterns within and across the anatomic families. Results:. Similar patterns of fit were observed within and across both families. The same size implants were not always used together across both systems. The strongest commonality was found regarding the percentage of the implant adjacent to more than 5 mm of cancellous bone (Gap, shown in red in Figure 1b) and the pattern of contact on the medial curvature of the implants. On average 61% and 56% of the metaphyseal region of Implants 1 and 2, respectively, is adjacent to 5–12 mm of cancellous bone between the implant and cortical bone. Implants 1 and 2 also demonstrated 30% and 37% between 0.5 and 5 mm of cancellous bone to the cortical boundary. Contact (< .5 mm) was only achieved in areas where bone would have been removed through femoral preparation. When maximizing fill, it was found that the percent Gap was reduced and distributed between conformity and proximity. There was also less variability between both systems when the goal was to maximize fill, however there was no statistical difference given the sample size between both stems regardless of method. Discussion:. Proper load transfer is essential for positive bone remodeling for short/long term fixation. As anatomic stems load femurs circumferentially, it is important to note that common characteristics transfer load to bone potentially contributing to their success. Previously, technology has not permitted circumferential analysis of implant fit on a wide scale, reproducible basis

Introduction:. The widespread use of TKA promoted studies on kinematics after TKA, particularly of the femorotibial joint. Knee joint kinematics after TKA, including the range of motion (ROM) and the physical performance, are also influenced by the biomechanical properties of the patella. Surgeons sometimes report complications after TKA involvinganterior knee pain, patellofemoral impingement and instability. However, only few studies have focused specially on the patella. Because the patella bone is small and overlapped with the femoral component on scan images. In addition, the patellar component in TKA is made of x-ray–permeable ultra-high molecular weight polyethylene. It is impossible to radiographically determine the external contour of the patellar component precisely. No methods have been established to date to track the dynamic in vivo trajectory of the patella component. In this study, we analyzed the in vivo three-dimensional kinematics of the patellar component in TKA by applying our image matching method with image correlations. Methods:. A computed tomography (CT) and an x-ray flat panel detector system (FPD) were used. FPD-derived post-TKA x-ray images of the residual patellar bone were matched by computer simulation with the virtual simulation images created using pre-TKA CT data. For the anatomic location of the patellar component, the positions of the holes drilled for the patellar component pegs were used. This study included three patients with a mean age of 68 years (three females with right knee replacement) who had undergone TKA with the Quest Knee System and achieved a mean passive ROM of 0 to ≥ 130° after 6 or more month post-TKA. We investigated three-dimensional movements of the patellar component in six degrees of freedom (6 DOF) during squatting and kneeling. Furthermore, we simulated the three-dimensional movement of the patellar component, and we estimated and visualized the contact points between the patellar and femoral components on a three-dimensional model. Results:. Average root mean square errors of this technique with the patellar bone of a fresh-frozen pig complete knee joint have been confirmed as 0.2 mm for the translations and 0.2 degrees for the rotation. The 6 DOF analysis results showed that patellar dynamics were similar for all subjects on squatting and kneeling. For the patellar rotation during squatting, only 1 to 2 additional degrees were noted for all subjects. During kneeling, the patellar rotation noted adduction for all subjects. The patellar contact point on the femoral component gradually showed superior shift, increasing the distance with knee flexion during squatting and kneeling (Fig, 1. 2). Discussions and Conclusions:. In this study, no patellar shifts were detected in rotation or tilt during squatting, suggesting that the patellar component remained in the positions designed for early stages of flexion. And the patellar component shifted towards the lateral side during squatting. This finding suggests the idea that the patellar movement reflected the design of the Quest Knee system. This study demonstrated that the analytical method is useful for evaluating the pathologies and post-surgical conditions of the knee and other joints

The purpose of this study is to investigate the three-dimensional (3D) kinematics of normal knees in deep knee-bending motions like squatting and kneeling. Material & Methods: We investigated the in vivo kinematics of 4 Japanese healthy male volunteers (8 normal knees in squatting, 7 normal knees in kneeling). Each sequential motion was performed under fluoroscopic surveillance in the sagittal plane. Femorotibial motion was analyzed using 2D/3D registration technique, which uses computer-assisted design (CAD) models to reproduce the spatial position of the femur and tibia from single-view fluoroscopic images. We evaluated the femoral rotation relative to the tibia and anteroposterior (AP) translation of the femoral sulcus and lateral epicondyle on the plane perpendicular to the tibial mechanical axis. Student's t test was used to analyze differences in the absolute value of axial rotation and AP translation of the femoral sulcus and lateral epicondyle during squatting and kneeling. Values of P < 0.05 were considered statistically significant. During squatting, knees were gradually flexed from −2.8 ± 1.3° to 145.5 ± 5.1° on average. Knees were gradually flexed from 100.8 ± 3.9° to 155.6 ± 3.2° on average during kneeling. Femurs during squatting displayed sharp external rotation relative to the tibia from 0° to 30° of flexion and it reached 12.5 ± 3.3° on average. From 30° to 130° of flexion, the femoral external rotation showed gradually, and it reached 19.1 ± 7.3° on average. From 130° to 140° of flexion, it was observed additionally, and reached 22.4 ± 6.1° on average. All kneeling knees displayed femoral external rotation relative to the tibia sharply from 100° to 150° of flexion, and it reached 20.7 ± 7.5° on average. From 100° to 120° of flexion, the femoral external rotation during squatting was larger than that during kneeling significantly. From 120° to 140° of flexion, there was no significant difference between squatting and kneeling. The sulcus during squatting moved 4.1 ± 4.8 mm anterior from 0° to 60° of flexion. From 60° of flexion it moved 13.6 ± 13.4 mm posterior. The sulcus during kneeling was not indicated significant movement with the knee flexion. The lateral epicondyle during squatting moved 39.4 ± 7.7 mm posterior from 0° to 140° of flexion. The lateral epicondyle during kneeling moved 22.0 ± 5.4 mm posterior movement from 100° to 150° of flexion. In AP translation of the sulcus from 100° to 140° of flexion, there was no significant difference between squatting and kneeling. However in that of the lateral epicondyle, squatting groups moved posterior significantly. Even if they were same deep knee-bending, the kinematics were different because of the differences of daily motions. The results in this study demonstrated that in vivo kinematics of deep knee-bending were different between squatting and kneeling

Purpose. The purpose of this study was to assess the accuracy of three-dimensional camera technology when monitoring deformity correction by an Ilizarov frame and to compare it to manual measurements. Methods and Results. A model consisting of an Ilizarov frame built around an artificial tibia and fibula was used with retro-reflective markers placed on the frame and bones to allow for the positions of each to be detected by the camera system. Measurements made by the camera system were compared to measurements taken manually. In the assessment of frame lengthening, the camera system average error was 2% (SD 2%) compared to 7% (SD 6%) for manual measurement. In the assessment of bone lengthening, the camera system average error was 4% (SD 4%) compared to 34% (SD 8%) for manual measurement. The technology also demonstrated good accuracy in the measurement of angular deformity changes. Conclusion. The results of this study demonstrate that the measurement of deformity correction with three-dimensional infra-red camera technology is superior to manual measurements in a model of deformity correction. This method could replace or greatly reduce x-ray exposure in monitoring deformity correction post-operatively

During total knee replacement (TKR), knee surgical navigation systems (KSNS) report in real time relative motion data between the tibia and the femur from the patient under anaesthesia, in order to identify best possible locations for the corresponding prosthesis components. These systems are meant to support the surgeon for achieving the best possible replication of natural knee motion, compatible with the prosthesis design and the joint status, in the hope that this kinematics under passive condition will be then the same during the daily living activities of the patient. Particularly, by means of KSNS, knee kinematics is tracked in the original arthritic joint at the beginning of the operation, intra-operatively after adjustments of bone cuts and trial components implantation, and after final components implantation and cementation. Rarely the extent to which the kinematics in the latter condition is then replicated during activity is analysed. As for the assessment of the active motion performance, the most accurate technique for the in-vivo measurements of replaced joint kinematics is three-dimensional video-fluoroscopy. This allows joint motion tracking under typical movements and loads of daily living. The general aim of this study is assessing the capability of the current KSNS to predict replaced joint motion after TKR. Particularly, the specific objective is to compare, for a number of patients implanted with two different TKR prosthesis component designs, knee kinematics obtained intra-operatively after final component implantation measured by means of KSNS with that assessed post-operatively at the follow-up by means of three-dimensional video-fluoroscopy. Thirty-one patients affected by primary gonarthrosis were implanted with a fixed bearing posterior-stabilized TKR design, either the Journey® (JOU; Smith&Nephew, London, UK) or the NRG® (Stryker®-Orthopaedics, Mahwah, NJ-USA). All implantations were performed by means of a KSNS (Stryker®-Leibinger, Freiburg, Germany), utilised to track and store joint kinematics intra-operatively immediately after final component implantation (INTRA-OP). Six months after TKR, the patients were followed for clinical assessment and three-dimensional video fluoroscopy (POST-OP). Fifteen of these patients, 8 with the JOU and 7 with the NRG, gave informed consent and these were analyzed. At surgery (INTRA-OP), a spatial tracker of the navigation system was attached through two bi-cortical 3 mm thick Kirschner wires to the distal femur and another to the proximal tibia. The conventional navigation procedure recommended in the system manual was performed to calculate the preoperative deformity including the preoperative lower limb alignment, to perform the femoral and tibial bone cuts, and to measure the final lower limb alignment. All these assessment were calculated with respect to the initial anatomical survey, the latter being based on calibrations of anatomical landmarks by an instrumented pointer. Patients were then analysed (POST-OP) by three-dimensional video-fluoroscopy (digital remote-controlled diagnostic Alpha90SX16; CAT Medical System, Rome-Italy) at 10 frames per second during chair rising-sitting, stair climbing, and step up-down. A technique based on CAD-model shape matching was utilised for obtaining three-dimensional pose of the prosthesis components. Between the two techniques, the kinematics variables analysed for the comparison were the three components of the joint rotation (being the relative motion between the tibial and femoral components represented using a standard joint convention, the translation of the line through the medial and lateral contact points (being these points assumed to be where the minimum distance between the femoral condyles and the tibial baseplate is observed) on the tibial baseplate and the corresponding pivot point, and the location of the instantaneous helical axes with the corresponding mean helical axis and pivot point. In all patients and in both conditions, physiological ranges of flexion (from −5° to 120°), and ab-adduction (±5°) were observed. Internal-external rotation patterns are different between the two prostheses, with a more central pivoting in NRG and medial pivoting in JOU, as expected by the design. Restoration of knee joint normal kinematics was demonstrated also by the coupling of the internal rotation with flexion, as well as by the roll-back and screw-home mechanisms, observed somehow both in INTRA- and POST-OP measurements. Location of the mean helical axis and pivot point, both from the contact lines and helical axes, were very consistent over time, i.e. after six months from intervention and in fully different conditions. Only one JOU and one NRG patient had the pivot point location POST-OP different from that INTRA-OP, despite cases of paradoxical translation. In all TKR knees analysed, a good restoration of normal joint motion was observed, both during operation and at the follow-up. This supports the general efficacy of the surgery and of both prosthesis designs. Particularly, the results here reported show a good consistency of the measurements over time, no matter these were taken in very different joint conditions and by means of very different techniques. Intra-operative kinematics therefore does matter, and must be taken into careful consideration for the implantation of the prosthesis components. Joint kinematics should be tracked accurately during TKR surgery, and for this purpose KSNS seem to offer a very good support. These systems not only supports in real time the best possible alignment of the prosthesis components, but also make a reliable prediction of the motion performance of the replaced joint. Additional analyses will be necessary to support this with a statistical power, and to identify the most predicting parameters among the many kinematics variables here analysed preliminarily

Introduction and Aims: There is a relationship between the anatomy of the hip joint and the development of arthritis. A common cause of hip pain in the young adult that can lead to arthritis is acetabular dysplasia. More recently, femoroacetabular impingement has been described as another cause of hip pain. The purpose of our study was to evaluate the applicability of pelvic computed tomography (CT) with three-dimensional surface rendering to evaluate femoro-acetabular impingement. Method Thirty-six hips (30 patients; 17 males; 13 females) with persistent hip pain, mean age 41 (37–52), underwent three-dimensional CT of the pelvis, as well as MRI arthrography with gadolinium enhancement. On 3D CT, the concavity of the femoral head-neck junction (offset), alpha angle as described by Notzli was calculated to depict the anterior femoral neck contour. The concavity of the posterior aspect of the head neck junction was measured as the beta angle. The same measurements were made in 20 hips, consisting of randomly selected patients with no prior history of hip pathology or pain (mean age 37; 13 males; eight females). Results The mean alpha angle for the symptomatic group was 66.4 (39–94) and 43.8 (39.3–48.3) for the control group (p=0.001). All symptomatic hips had abnormal findings on MRA: labral tears in all; cartilage delamination/ulceration in 14 hips; herniation pits in six hips. The majority of labral tears and delamination were located in the antero-superior quadrant. In the surgical treated group, all MRA findings were confirmed. The mean beta angle was significantly smaller (increase concavity) in the symptomatic versus the controls: 40.2 versus 43.8 (p=0.011). Interestingly in the symptomatic group the beta angle was significantly lower than the alpha angle (p< 0.02), but not in the controls. Conclusion: 3D CT with surface rendering and multiplanar reformation is useful to determine degree of bone buttressing of the anterior femoral head-neck junction quantitatively assessed by alpha angle measurement, which is elevated in patients with femoro-acetabular impingement. With a greater posterior concavity i.e. small beta angle in the symptomatic group versus the control, subclinical slipped femoral epiphysis remains a plausible cause of this deformity

Objectives. Whilst gait speed is variable between healthy and injured adults, the extent to which speed alone alters the 3D in vivo knee kinematics has not been fully described. The purpose of this prospective study was to understand better the spatiotemporal and 3D knee kinematic changes induced by slow compared with normal self-selected walking speeds within young healthy adults. Methods. A total of 26 men and 25 women (18 to 35 years old) participated in this study. Participants walked on a treadmill with the KneeKG system at a slow imposed speed (2 km/hr) for three trials, then at a self-selected comfortable walking speed for another three trials. Paired t-tests, Wilcoxon signed-rank tests, Mann-Whitney U tests and Spearman’s rank correlation coefficients were conducted using Stata/IC 14 to compare kinematics of slow versus self-selected walking speed. Results. Both cadence and step length were reduced during slow gait compared with normal gait. Slow walking reduced flexion during standing (10.6° compared with 13.7°; p < 0.0001), and flexion range of movement (ROM) (53.1° compared with 57.3°; p < 0.0001). Slow walking also induced less adduction ROM (8.3° compared with 10.0°; p < 0.0001), rotation ROM (11.4. °. compared with 13.6. °. ; p < 0.0001), and anteroposterior translation ROM (8.5 mm compared with 10.1 mm; p < 0.0001). Conclusion. The reduced spatiotemporal measures, reduced flexion during stance, and knee ROM in all planes induced by slow walking demonstrate a stiff knee gait, similar to that previously demonstrated in osteoarthritis. Further research is required to determine if these characteristics induced in healthy knees by slow walking provide a valid model of osteoarthritic gait. Cite this article: N. Mannering, T. Young, T. Spelman, P. F. Choong. Three-dimensional knee kinematic analysis during treadmill gait: Slow imposed speed versus normal self-selected speed. Bone Joint Res 2017;6:514–521. DOI: 10.1302/2046-3758.68.BJR-2016-0296.R1

This randomised study compared outcomes in patients with displaced fractures of the clavicle treated by open reduction and fixation by a reconstruction plate which was placed either superiorly or three-dimensionally. Between 2003 and 2006, 133 consecutive patients with a mean age of 44.2 years (18 to 60) with displaced midshaft fractures of the clavicle were allocated randomly to a three-dimensional (3D) (67 patients) or superior group (66). Outcome measures included the peri-operative outcome index, delayed union, revision surgery and symptoms beyond 16 weeks. CT was used to reconstruct an image of each affected clavicle and Photoshop 7.0 software employed to calculate the percentage of the clavicular cortical area in the sagittal plane. The patients were reviewed clinically and radiographically at four and 12 months after the operation. The superior plate group had a higher rate of delayed union and had more symptomatic patients than the 3D group (p < 0.05). The percentage comparisons of cortical bone area showed that cortical bone in the superior distal segment is thicker than in the inferior segment, it is also thicker in the anterior mid-section than in the posterior (p < 0.05). If fixation of midshaft fractures of the clavicle with a plate is indicated, a 3D reconstruction plate is better than one placed superiorly, because it is consistent with the stress distribution and shape of the clavicle

Introduction: Leg length and offset restoration are known to improve function after total hip arthroplasty, and to minimize the risk of dislocation and limp. Anatomic data of the hip are needed to determine specifications for prosthesis design that restore patient hip anatomy more closely. Furthermore, femoral off-set values calculated on X-Rays may be inaccurate in case of external rotational contracture or high femoral ante-version. The goal of this study was to determine three-dimensional morphological data of the hip in case of primary osteoarthritis, especially for femoral off-set. Material and Method: 223 hips with primary osteoarthritis have been analysed using a CT-scan and a specific software (HIP-PLAN. ®. ) that allows image post-processing for re-orienting the pelvis or the femur to a standardized orientation. Femoral and acetabular anteversions were measured. The planar (2D) and three-dimensional (3D) values of femoral offset were determined. 3D values were measured as the distance between the femoral head centre and the diaphyseal femur axis; 2D values were calculated as the projection of this distance on the frontal plan. Results: Measurements precision was good with correlation scores ranging between 0.91 and 0.99. Mean acetabular anteversion angle was 26° +/−6.6° when measured in the Anterior Pelvic Plane and 21.9° +/−6.6° in the frontal plane according to the method of Murray. Mean femoral anteversion was 21.9° +/−9.4 according to the method of Murphy. The Sum of acetabular and femoral anteversion was found to be out of the safe zone regarding dislocation risk in 47% of patients. Mean 3D femoral off-set was found to be 42.2 mm+/− 5, significantly increased by 3.5 mm +/− 2.5 when compared to the 2D femoral off-set values. Femoral off-set was above 45mm in 31% of cases and higher than 50 mm in 12% of cases. The tip of the great trochanter was located higher than the femoral head centre, at a mean distance of about 9 mm. Discussion: When measured on X-rays, femoral off-set may be significantly under-estimated. This error is probably due to the external rotational contracture of the hip induced by osteoarthritis. If the implants are positioned using the anatomical preoperative anteversion angles, 47% of patients would not be in the safe zone regarding posterior dislocation risk. Conclusions: Planar measurement using X-Rays underestimates significantly the femoral off-set. Neck and head modularity may be useful to achieve simultaneous restoration of femoral off-set and leg length in 12 to 31% of cases

Although it is clear that opening-wedge high tibial osteotomy (HTO) changes alignment in the coronal plane, which is its objective, it is not clear how this procedure affects knee kinematics throughout the range of joint movement and in other planes. Our research question was: how does opening-wedge HTO change three-dimensional tibiofemoral and patellofemoral kinematics in loaded flexion in patients with varus deformity?Three-dimensional kinematics were assessed over 0° to 60° of loaded flexion using an MRI method before and after opening-wedge HTO in a cohort of 13 men (14 knees). Results obtained from an iterative statistical model found that at six and 12 months after operation, opening-wedge HTO caused increased anterior translation of the tibia (mean 2.6 mm, p <  0.001), decreased proximal translation of the patella (mean –2.2 mm, p <  0.001), decreased patellar spin (mean –1.4°, p < 0.05), increased patellar tilt (mean 2.2°, p < 0.05) and changed three other parameters. The mean Western Ontario and McMaster Universities Arthritis Index improved significantly (p < 0.001) from 49.6 (standard deviation (. sd. ) 16.4) pre-operatively to a mean of 28.2 (. sd. 16.6) at six months and a mean of 22.5 (. sd.  14.4) at 12 months. The three-dimensional kinematic changes found may be important in explaining inconsistency in clinical outcomes, and suggest that measures in addition to coronal plane alignment should be considered. . Cite this article: Bone Joint J 2014; 96-B:1214–21

Introduction: The purpose of this study was to evaluate the impact of volume rendering 3D computed tomography reconstructions on the inter- and intraobserver reliability of the OTA/AO and Neer classifications in the assessment of proximal humerus fractures. Material and Methods: Four observers with different levels of clinical training classified forty proximal humerus fractures according to the OTA/AO and Neer classifications. Three rounds of evaluation were performed and compared. First, fractures were classified on the basis of plain radiographs alone. Then, four weeks later, the combination of plain radiographs and computed tomography scans with conventional 3D SSD reconstructions was evaluated. Finally, four weeks later, the combination of plain radiographs, computed tomography scans, and 3D volume rendering reconstructions was assessed. These readings were repeated in a newly randomized order after an interval of twelve weeks to evaluate intraobserver reliability. Results: Interobserver reliability for the AO/ASIF classification showed good interobserver reliability with plain radiographs (k=0,65) and two-dimensional CT scans with conventional three-dimensional (SSD) reconstructions (k=0,71). Interobserver reliability improved to excellent when the fractures were classified on the basis of 3D volume rendering reconstructions scans (k=0,84). Intraobserver reliability of the OTA/AO classification was good with plain radiographs (k=0,70) and improved to excellent after adding three-dimensional SSD reconstructions (k=0,80) and three-dimensional VR reconstructions (k=0,88). Interobserver reliability of the Neer classification was poor with plain radiographs (k=0,39) and moderate with two-dimensional CT scans and conventional three-dimensional (SSD) reconstructions (k=0,56) and improved to good with the addition of 3D VR scans (k=0,74). Intraobserver reliability for was poor with plain radiographs (k=0,34), good with three-dimensional SSD reconstructions (k=0,61), and excellent with three-dimensional VR reconstructions (k=0,80). Conclusion: In this study, three-dimensional volume rendering computed tomography improved the inter- and intraobserver reliability of the AO/OTA and the Neer classifications in the assessment of proximal humerus fractures. In the opinion of the authors, 3D volume rendering CT-scans are a helpful tool for preoperative planning and classification of fractures of the proximal humerus

Introduction. According to the literature, the gait does not return to normal after THA. However, the three-dimensional hip anatomy is usually not assessed before and after surgery. Our hypothesis was that an accurate reconstruction of the hip anatomy, based on a three-dimensional preoperative planning, may normalize the gait after THA. Material and method. 18 consecutive patients, graded Charnley A, aged of 59.3 ±13 years, underwent THA for unilateral primary osteoarthritis using a direct anterior minimal invasive approach. A 3D computerised planning was performed, the implants size and position were chosen in order to restore, the leg length, the off-set, the centre of rotation and the anteversion angles (Figure 1). At 1 year follow up, a 3D gait analysis was performed and included 29 parameters describing the kinetics and the kinematics. Each patient was compared to himself using the contra-lateral healthy hip, as well as to a group of 13 healthy volunteers. Results. The real implants were the same than the ones planned in all the patients. The hip anatomy was restored with a high accuracy: 0.1±3mm for the hip rotation centre, −1.4±3 mm for the leg length and −0.9±3.5mm for the femoral offset. With respect to the gait, there was no significant difference between the operated side and the control-lateral leg. When compared to the control group, all the patients were within the normal range for all the parameters (Figure 2). Discussion and conclusion. The results suggest that the combination of an accurate 3D reconstruction and a direct anterior minimal invasive approach may allow to achieve a normal gait after THA at one year follow up

Patellofemoral Pain Syndrome is characterized by anterior knee pain during activities such as squatting that is thought to be caused by abnormal patellar motion. However, the causative role has yet to be verified since it is difficult to measure the three-dimensional kinematics of the patellofemoral joint (PFJ) in vivo. We developed a fluoroscopy-based method to measure patellar motion as it moves under load through a cycle of flexion and compared the results with those obtained using Roentgen Stereophotogrammetric Analysis (RSA). Our data suggest that the fluoroscopy-based method has sufficient accuracy to detect clinically significant differences in patterns of patellar motion. The purpose of our study was to determine how accurately a fluoroscopy-based method measures patellar tracking. Our method measures three-dimensional PFJ kinematics with sufficient accuracy to be of clinical value in assessing dynamic motion. Patellar tracking can be assessed during aggravating activities to identify specific tracking abnormalities related to anterior knee pain. Four cadaver knees were imaged using computed tomography (CT). Surface models were generated and the coordinates of implanted tantalum beads (in the femur, patella, and tibia) were determined. A series of fluoroscopic images were taken with the knees loaded in a rig at various flexion angles. Each calibrated fluoroscopic image was registered to the CT model using a point-based method such that the high-resolution CT model was matched to the position of knee flexion associated with each fluoroscopic image. The patellar orientation and position relative to the femur was then reconstructed and described using a gyroscopic joint coordinate system. Measurements were made under the same test conditions using the established uniplanar RSA technique. Fluoroscopy-based and RSA-based measures of patellar orientation and position were compared. The mean measurement error (SD) for patellar flexion, spin, and tilt was 1.86 (1.55), 1.16 (1.14), and 1.15 (1.10) degrees, respectively. For proximal, lateral and anterior patellar translation, the mean measurement error (SD) was 2.11 (2.16), 0.59 (0.47), and 1.24 (1.18) mm, respectively. The accuracy of the fluoroscopy-based method of measuring PFJ kinematics was poorer than the reported accuracy of RSA but appears to be sufficiently low to be of clinical value. Funding: Supported by an operating grant from the Canadian Institutes for Health Research and a Strategic Grant from the Natural Sciences and Engineering Research Council. NJM is supported by TAS/CIHR Partnership Fund

We evaluated the accuracy of a Magnetic Resonance Imaging (MRI)-based method to measure three-dimensional patellar tracking during loaded knee flexion. This method determines the relative positions of the knee bones by shape matching high-resolution three-dimensional geometric models of these bones to fast low-resolution scans taken during loaded flexion. The accuracy of the method’s assessment of patellar position and orientation was determined by comparing test measurements in four cadaver specimens to measurements made in the same specimens using Roentgen Stereophotogrammetric Analysis (RSA). This MRI-based method is more accurate than current two-dimensional imaging methods. The purpose of this study was to determine the accuracy of a MRI-based technique for measuring patellar tracking in loaded flexion. This novel, noninvasive, MRI-based method measures three-dimensional patellar tracking during loaded knee flexion with sufficient accuracy to detect clinically significant changes. Although abnormal patellar tracking is widely believed to be associated with pain and cartilage degeneration at the patella, these relationships have not been clearly established because most current methods assess only the two-dimensional alignment of the patella at one position. Measurements possible with this method should be sufficiently accurate to yield new insights into these relationships. Four cadaver knee specimens were flexed through seventy-five degrees of flexion in an MRI-compatible knee loading rig. A high-resolution image was acquired with each knee in extension and then a series of low-resolution scans (in two slice directions: axial and sagittal) were acquired through a flexion cycle. Segmenting bone outlines from high-resolution scans generated models of the femur, tibia and patella. These models were shape matched to the segmented bone outlines in the low resolution scans. Patellar attitude and position were determined and compared to measurements made using RSA. The mean measurement error in every kinematic parameter was lower for “fast” sagittal plane slices than for “fast” axial plane slices. In general, the mean measurement error was increased by decreasing the number of low-resolution slices. This method is more accurate than many two-dimensional methods, exposes participants to no ionizing radiation, and can be used through a large range of loaded knee flexion. Funding: Supported by an operating grant from the Canadian Institutes for Health Research and a Strategic Grant from the Natural Sciences and Engineering Research Council. NJM is supported by the Arthritis Society/CIHR Partnership Fund. Please contact author for figures and/or tables

Unknown femur orientation during X-ray imaging may cause inaccurate radiographic measurements. The aim of this study was to assess the effect of 3D femur orientation during radiographic imaging on the measurement of greater trochanter to femoral head centre (GT-FHC) distance. Three-dimensional femoral shapes (n=100) of unknown gender were generated using a statistical shape model based on a training data of 47 CT segmented femora. Rotations in the range of 0° internal to 50° external and 50° of flexion to 0° of extension (at 10 degree increments) were applied to each femur. A ray tracing algorithm was then used to create 2D images representing radiographs of the femora in known 3D orientations. The GT-FHC distance was then measured automatically by identifying the femoral head, shaft axis and tip of greater trochanter. Uniaxial rotations had little impact on the measurement with mean absolute error of 0.6 mm and 3.1 mm for 50° for pure external rotation and 50° pure flexion, respectively. Combined flexion and external rotation yielded more significant errors with 10° around each axis introducing a mean error of 3.6 mm and 20° showing an average error of 8.8 mm (Figure 1.). In the cohort we studied, when the femur was in neutral orientation, the tip of greater trochanter was never below the femoral head centre. Greater trochanter to femoral head centre measurement was insensitive to rotations around a single axis (i.e. flexion or external rotation). Modest combined rotations caused the tip of greater trochanter to appear more distal in 2D and led to deviation from the true value. This study suggests that a radiograph with the greater trochanter appearing below femoral head centre may have been acquired with 3D rotation of the femur. For any figures or tables, please contact the authors directly by clicking on ‘Info & Metrics’ above to access author contact details

A clinical and radiological study was conducted on 97 total hip replacements performed for congenital hip dislocation in 79 patients between 1989 and 1998 using a three-dimensional custom-made cementless stem. The mean age at operation was 48 years (17 to 72) and the mean follow-up was for 123 months (83 to 182). According to the Crowe classification, there were 37 class I, 28 class II, 13 class III and 19 class IV hips. The mean leg lengthening was 25 mm (5 to 58), the mean pre-operative femoral anteversion was 38.6° (2° to 86°) and the mean correction in the prosthetic neck was −23.6° (−71° to 13°). The mean Harris hip score improved from 58 (15 to 84) to 93 (40 to 100) points. A revision was required in six hips (6.2%). The overall survival rate was 89.5% (95% confidence interval 89.2 to 89.8) at 13 years when two hips were at risk. This custom-made cementless femoral component, which can be accommodated in the abnormal proximal femur and will correct the anteversion and frontal offset, provided good results without recourse to proximal femoral corrective osteotomy

Pre-operative computerised three-dimensional planning was carried out in 223 patients undergoing total hip replacement with a cementless acetabular component and a cementless modular-neck femoral stem. Components were chosen which best restored leg length and femoral offset. The post-operative restoration of the anatomy was assessed by CT and compared with the pre-operative plan. The component implanted was the same as that planned in 86% of the hips for the acetabular implant, 94% for the stem, and 93% for the neck-shaft angle. The rotational centre of the hip was restored with a mean accuracy of 0.73 mm (. sd. 3.5) craniocaudally and 1.2 mm (. sd. 2) laterally. Limb length was restored with a mean accuracy of 0.3 mm (. sd. 3.3) and femoral offset with a mean accuracy of 0.8 mm (. sd. 3.1). This method appears to offer high accuracy in hip reconstruction as the difficulties likely to be encountered when restoring the anatomy can be anticipated and solved pre-operatively by optimising the selection of implants. Modularity of the femoral neck helped to restore the femoral offset and limb length

Introduction: The goal of the study was to determine the precision of a three-dimensional pre-operative planning tool using a specific software (HIP-PLAN. ®. ) and an anatomic cementless neck-modular stem. Method: 223 patients who underwent a primary total hip replacement had a CT Scan before and after surgery. A pre-operative three-dimensional planning based on the CT-scan was performed. A cementless cup and a neck-modular stem were used. A computational matching of the pre-operative and the post-operative CT-scans was performed in order to compare the values of the planned anteversions and the planned displacement of the hip rotation center to the post-operative values. Results: The implanted component was the same as the one planned in 89% for the cup and 94% for the stem. For the mean femoral anteversion, there was no significant difference between the planned value (26.1° +/−11.8) and the post-operative value (26.9° +/−14.1). There was a poor correlation between the planned values and the actual ones for the acetabular cup anteversion (coefficient 0.17). The hip rotation center was restored with a precision of 0.73 mm +/3.5 horizontally and 1.2 mm +/−2 laterally. Limb length was restored with a precision of 0.3 mm +/−3.3 and the femoral off-set with a precision of 0.8 mm +/−3.1. There was no significant modification of the femoral off-set (0.07 p=0.7) which was restored or slightly increased in 93% of cases. Almost all the surgical difficulties were predicted. Conclusion: HIP-PLAN. ®. software is a reliable three-dimensional pre-operative planning tool which allows acurate prediction of components and hip anatomy

Introduction. Geometric variations of the hip joint can give rise to repeated abnormal contact between the femur and acetabular rim, resulting in cartilage and labrum damage. Population-based geometric parameterisation can facilitate the flexible and automated in silico generation of a range of clinically relevant hip geometries, allowing the position and size of cams to be defined precisely in three dimensions. This is advantageous compared to alpha angles, which are unreliable for stratifying populations by cam type. Alpha angles provide an indication of cam size in a single two-dimensional view, and high alpha angles have been observed in asymptomatic individuals. Parametric geometries can be developed into finite element models to assess the potential effects of morphological variations in bone on soft tissue strains. The aim of this study was to demonstrate the capabilities of our parameterisation research tool by assessing impingement severity resulting from a range of parametrically varied femoral and acetabular geometries. Methods. Custom made MATLAB (MathWorks) and Python codes. [1]. were used to generate bone surfaces, which were developed into finite element models in Abaqus (SIMULIA). Parametric femoral surfaces were defined by a spherical proximal head and ellipse sections through the neck/cam region. This method produced surfaces that were well fitted to bone geometry segmented from CT scans of cam patients and capable of producing trends in results similar to those found using segmented models. A simplified spherical geometry, including the labrum and acetabular cartilage, represented the acetabulum. Femoral parameters were adjusted to define relevant variations in cam size and position. Two radii (small and large cams) and two positions (anterior and superior cams) were defined resulting in four models. Alpha angles of these parametric femurs were measured in an anterior-posterior view and a cross-table lateral view using ImageJ (NIH). A further model was developed using a femur with a medium cam size and position, and the level of acetabular coverage and labrum length were varied. Bones were modelled as rigid bodies and soft tissues were modelled as transversely isotropic linearly elastic materials. With the acetabulum fully constrained in all cases, the femurs were constrained in translation and rotated to simulate flexion followed by internal rotation to cause impingement against the labrum. Results and Discussion. Models generated using the parametric approach showed that potential for tissue damage, indicated through local strain, was not predicted by measured alpha angle, but resulted from cam extent and position as defined by the ellipses. When variations were made to the acetabular rim, an increase in bone coverage had the greatest effect on impingement severity, indicated by strain in the cartilage labral-junction. An increase in labral length increased labral displacement, but had less effect on cartilage-labral strain. Patient specific models currently require full image segmentation, but there is potential to further develop these parametric methods to assess likely impingement severity based on a series of measures of the neck and acetabulum when three-dimensional imaging of patients is available

Objective. To three-dimensionally reconstruct the proximal femur of DDH (Developmental dysplasia of the hip) and measure the related anatomic parameters, so that we could have a further understanding of the morphological variation of the proximal femur of DDH, which would help in the preoperative planning and prosthesis design specific for DDH. Methods. From Jan.2012 to Dec.2014, 38 patients (47 hips) of DDH were admitted and 30 volunteers (30 hips) were selected as controls. All hips from both groups were examined by CT scan and radiographs. The Crowe classification method was applied. The CT data were imported into Mimics 17.0. The three-dimensional models of the proximal femur were then reconstructed, and the following parameters were measured: neck-shaft angle, neck length, offset, height of the centre of femoral head, height of the isthmus, height of greater trochanter, the medullary canal diameter of isthmus(Di), the medullary canal diameter 10mm above the apex of the lesser trochanter(DT+10), the medullary canal diameter 20mm below the apex of the lesser trochanter(DT-20), and then DT+10/Di, DT-20/Di and DT+10/DT-20 were calculated. Results. There is no significant difference in neck-shaft angle between Crowe I-III DDH and the control group, while the neck-shaft angle is much smaller in Crowe IV DDH. The neck length of Crowe IV DDH is much smaller than those of Crowe I-III DDH. As for Di there is neither significant difference between Crowe I DDH and the control group, nor significant difference between CroweII-III and Crowe IV, but the difference is significant between the first two groups and the latter two groups. DT+10/DT-20 and the offset have no significant difference between the control group and DDH groups. DT-20, DT+10, DT+10/Di and DT-20/Di are much smaller in Crowe IV DDH than that in Crowe I-III and the control groups. Height of greater trochanter in Crowe IV is larger than those in Crowe I-III and the control group. Height of the centre of femoral head in Crowe IV DDH is smaller than those in Crowe I-III DDH and the control group. The height of the isthmus in Crowe IV is much smaller than those in Crowe I-III DDH and the control group. Conclusion. The neck-shaft angle in DDH groups is not larger than that in the control group, while in contrast, it's much smaller in Crowe IV DDH than that in the control group. Comparing to Crowe I-III DDH and the control group, Crowe IV DDH has a dramatic change in the intramedullary and extramedullary parameters. The isthmus and the great trochanter are higher and there is apparent narrowing of the medullary canal around the level of the lesser trochanter

In cases of severe postdysplastic coxarthosis, it seems to be impossible to recognize acetabular geometry and the real femoral position on a plain X-ray because the real diameters and angles can be disfigured when projected. Computed tomography (CT) provides important information to the surgeon about the concavity, shape and stereotomy of the acetabulum. It is quite difficult to correctly evaluate severely changed hips. CT displays more precise acetabular diameters and angles than a plain radiograph. Because of the high density of bony tissue, the CT makes it easy to produce a three-dimensional display of the hip. From September 1995 to December 1998, 224 patients (148 female, 76 male) underwent arthroplasty using a non-cemented prosthesis according to Zweymüller. A total of 236 hip joints were operated and classified as Crowe Group I (76 hips), Crowe Group II (149 hips), and Crowe Group III (11 hips). There were no Crowe Group IV hips. A total of 96 patients were examined by 3D CT in preoperative planning. Based on CT results, four joints were not recommended for an operative solution. CT protocol: scanner Elscint TWIN II, slice 2.5 mm, 120 kV, 285 mAs, matrix 3402,. No. of slices: 40–50, incremental dual acquisition. Postprocessing: axial images, multiplanar reconstructions, 3D SSD. Acetabular stereometry: superoinferior diameter, anteroposterior diam., depth, bottom thickness, femoral neck anteversion angle and subtrochanteric marrow diameter. A three-dimensional CT of the hip is a very effective tool for preoperative assessment

Minimally invasive (MIS) screw fixation for Hangman's fracture can decrease iatrogenic soft-tissue injury compared with conventional open approach, but increase the risk of instrumentation-related complications due to lack of anatomical landmarks. With the advantages, the intra-operative three-dimensional fluoroscopy-based navigation (ITFN) system seems to be an inherent partner for MIS techniques. The purpose of this study was to evaluate the accuracy and feasibility of MIS techniques incorporating with ITFN for treating Hangman's fracture. 20 patients with Hangman's fracture underwent C2-C3 pedicle screw fixation using ITFN. 6 patients used MIS technique, with the other 14 patients using conventional open technique. Preoperative visual analogue score (VAS) was 5.7±1.4 in CAOS-MIS group and 5.5±0.9 in CAOS-open group. Operative time, blood loss and postoperative neurovascular complications were recorded. The accuracy of screw positions was studied by postoperative CT scan. All patients were followed up for at least 6 months and the fusion status was ascertained by dynamic radiographs. The average operative time was 134.2±8.0 min in CAOS-MIS group and 139.3±25.8 min in CAOS-open group, and there was no significant difference between the two (p&gt;0.01). The blood loss was 66.7±25.8 ml in CAOS-MIS group and 250.0±141.4 ml in CAOS-open group. Statistical difference existed with CAOS-MIS group significant less than CAOS-open group (p&lt;0.01). A total of 80 screws were inserted. No screw-related neurovascular injury was observed. Post-operative CT scan revealed 83.3% (20/24) screws of grade 1 and 16.7% screws of grade 2 (4/24) in CAOS-MIS group, meanwhile 89.3% screws of grade 1 (50/56) and 10.7% screws of grade 2 (6/56) in CAOS-open group. There was no grade 3 screw detected. Fisher's exact test showed there was no statistical difference between these two groups (p&gt;0.01). There was no statistical difference in pre-operative VAS between these two groups (p&gt;0.01). Compared with the CAOS-open group (1.7±0.6), neck pain VAS at 6-month follow-up in CAOS-MIS group (0.3±0.5) was significantly lower (p&lt;0.01). Solid fusion was demonstrated in all the cases by dynamic radiographs. So it is feasible and safe for percutaneous minimally invasive C2-C3 pedicle screw fixation for Hangman's fracture using intra-operative three-dimensional fluoroscopy-based navigation, which can also decrease the incidence of post-operative neck pain

The evaluation of knee stability is fundamental for the clinical discrimination between healthy and pathological joints, for the design and evaluation of prostheses and for the definition of articular models. Knee stability can be quantified by measuring the relation between applied single-axis constant loads and corresponding tibio-femoral displacements (i.e., translations and rotations), namely the joint stiffness, at a given flexion angle. No many studies are available in the literature on this topic [1–3]. In particular, the translations/rotations along/about directions different from the loaded one were not deeply investigated. A fresh frozen lower-limb specimen (female, 63 years old, weight 68 Kg, height 158 cm) was considered. The forefoot and all soft tissues outside the knee were removed by a surgeon, keeping the knee joint capsule intact. A stereophotogrammetric system (Vicon Motion Systems Ltd.) was used to measure the femoro-tibial relative motion by two trackers fixed to the bones, thus introducing no soft-tissue artifact. The specimen was then mounted on a test rig capable to exert general loading conditions [4], and constant loads were applied to the tibia: ±100 N in antero-posterior (AP) and medio-lateral (ML) direction; ±10 Nm about abb-adduction (AA) and in-external (IE) rotations. Loads were applied approximately at the mid-point between the lateral and medial epicondyles, and were kept constant while the femur was flexed over a 135° range. Displacements were defined with respect to the joint natural motion (RTNM), also registered with the same rig. The relative motion of the bones was expressed by a standard joint coordinate system [5]. Considerable translations/rotations appeared also on different directions than the loaded one. At 90° of flexion, an anterior load of +100 N produced 5.5 mm of anterior translation, 10.9 mm of medial translation and 12° of external rotation of the tibia (RTNM). When not directly loaded in ML and IE directions, the tibia translated medially and rotated externally, independently from the sign of the applied load: at 90° of flexion, an AA torque of +10 Nm and −10 Nm produced respectively 5 mm and 8.9 mm of medial translation, and 5.5° and 7.5° of external rotation of the tibia (RTNM). The load/displacement relation was highly non linear also for the loading direction. At 90° of flexion, IE torques of +10 Nm and −10 Nm produced respectively 3.6° of internal and 14.2° of external rotation of the tibia (RTNM). The knee joint structures make the relation between applied loads and bone displacements highly non linear. As a result, a load acting on one direction produces a complex three-dimensional joint motion. Future work will extend the presented analysis on several specimens, also increasing the magnitude and the number of loading conditions

The gelatin-based haemostyptic compound Spongostan was tested as a three-dimensional (3D) chondrocyte matrix in an in vitro model for autologous chondrocyte transplantation using cells harvested from bovine knees. In a control experiment of monolayer cultures, the proliferation or de-differentiation of bovine chondrocytes was either not or only marginally influenced by the presence of Spongostan (0.3 mg/ml). In monolayers and 3-D Minusheet culture chambers, the cartilage-specific differentiation markers aggrecan and type-II collagen were ubiquitously present in a cell-associated fashion and in the pericellular matrix. The Minusheet cultures usually showed a markedly higher mRNA expression than monolayer cultures irrespective of whether Spongostan had been present or not during culture. Although the de-differentiation marker type-I collagen was also present, the ratio of type-I to type-II collagen or aggrecan to type-I collagen remained higher in Minusheet 3-D cultures than in monolayer cultures irrespective of whether Spongostan had been included in or excluded from the monolayer cultures. The concentration of GAG in Minusheet cultures reached its maximum after 14 days with a mean of 0.83 ± 0.8 μg/10. 6. cells; mean ±, . sem. , but remained considerably lower than in monolayer cultures with/without Spongostan. Our results suggest that Spongostan is in principle suitable as a 3-D chondrocyte matrix, as demonstrated in Minusheet chambers, in particular for a culture period of 14 days. Clinically, differentiating effects on chondrocytes, simple handling and optimal formability may render Spongostan an attractive 3-D scaffold for autologous chondrocyte transplantation

Objectives. There remains a lack of data on the reliability of methods to estimate tibial coverage achieved during total knee replacement. In order to address this gap, the intra- and interobserver reliability of a three-dimensional (3D) digital templating method was assessed with one symmetric and one asymmetric prosthesis design. Methods. A total of 120 template procedures were performed according to specific rotational and over-hang criteria by three observers at time zero and again two weeks later. Total and sub-region coverage were calculated and the reliability of the templating and measurement method was evaluated. Results. Excellent intra- and interobserver reliability was observed for total coverage, when minimal component overhang (intraclass correlation coefficient (ICC) = 0.87) or no component overhang (ICC = 0.92) was permitted, regardless of rotational restrictions. Conclusions. Measurement of tibial coverage can be reliable using the templating method described even if the rotational axis selected still has a minor influence

A new method of recording the three-dimensional anatomy of the proximal femur from a single anteroposterior radiograph is described. This technique shows that in Perthes' disease the femoral head and neck are in significant anteversion and true varus. This anatomical configuration may be important in the pathogenesis and treatment of this disorder

Summary Statement. We successfully delineated the 3D micro morphology of chondrocytes in patella-patellar tendon using IL-XPCT for the first time. Compared with conventional histology, IL-XPCT can not only provide a higher resolution imgaing but also keep the 3D integrity of the specimen. Introduction. The morphology of the bone-tendon junction was complex and quite different from other organs, which result the injured bone-tendon junction repair process too slowly. To study the micro morphology of the bone-tendon junction in 3D may have a great significant value to revealing the repair mechanisms of this pathological process and accelerating injured bone-tendon junction repair. However, it was hindered by the convention methods such as histologic section. In our study, a novel imaging tool, synchrotron radiation based in-line x-ray phase contrast imaging (IL-XPCT) was used to research the 3D micro morphology of the bone-tendon junction. Methods. 1) Sample Preparation: 3 patella-patellar tendons was harvested from the knee joint of New Zealand adult rabbits and was immediately fixed, rinsed in water for 2 hours. Dehydration was done using a series of graded ethanol. The sample was cut out for the CCD pixel resolution in sagittal section. 2) Image Acquisition: The IL-XPCT was performed at the BL13W1 of the Shanghai Synchrotron Radiation Facility (SSRF) in China. The CCD pixel resolution was 0.74 μm. Image Acquisition include three steps, such as the the acquisition of tomo projections, CT slices and and 3D reconstruction of patella-patellar tendon on full scale by using VG Studio Max version 2.1. 3) Histological characterization observation: After scanning, the specimen was cut to histologic sectioning and used for morphology staining by safranin O staining and H&E staining. The histological morphology then compared with the IL-XPCT imaging dateset. Results. (1) The tissue gradations of patella-patellar tendon are clearly detected by IL-XPCT. (2) The 3D reconstruction image of patella-patellar tendon sample were largely match with the histological morphology stained by safranin O and H&E in sagittal view. (3) After the image segmentation, the 3D micro morphology of the bone-tendon junction could be vividly visualised in multi-angles. Through manipulate threshold of the 3D image, we can successfully obtained the 3D morphology of the chondrocyte, and the smallest diameter is approximately 5μm. Discussion & Conclusion. In the present study, we successfully delineated the 3D micro morphological features of chondrocytes in normal patella-patellar tendon using SR-based IL-XPCT for the first time. Compared with conventional histology, IL-XPCT can not only provide a higher resolution ratio without distortion but also keep the three-dimensional integrity of the specimen. Above all, IL-XPCT opens access to a new dimension in the morphological investigation of bone-tendon junction tissues, giving important complementary information to the conventional morphological analyses in view of the three-dimensional composition of bone-tendon junction tissues, On the other hand, it could be helpful to understanding the repair processes of bone-tendon junction injury and promoting the injured bone-tendon junction repair fast and high quality

This study examined the relationship between the cross-over sign and the true three-dimensional anatomical version of the acetabulum. We also investigated whether in true retroversion there is excessive femoral head cover anteriorly. Radiographs of 64 hips in patients being investigated for symptoms of femoro-acetabular impingement were analysed and the presence of a cross-over sign was documented. CT scans of the same hips were analysed to determine anatomical version and femoral head cover in relation to the anterior pelvic plane after correcting for pelvic tilt. The sensitivity and specificity of the cross-over sign were 92% and 55%, respectively for identifying true acetabular retroversion. There was no significant difference in total cover between normal and retroverted cases. Anterior and posterior cover were, however, significantly different (p < 0.001 and 0.002). The cross-over sign was found to be sensitive but not specific. The results for femoral head cover suggest that retroversion is characterised by posterior deficiency but increased cover anteriorly

Introduction. For anatomical reconstruction in shoulder arthroplasty, it is important to understand normal glenohumeral geometry. Unfortunately, however, the details of the glenohumeral joint in Asian populations have not been sufficiently evaluated. There is a racial difference in body size, and this difference probably results in a difference in glenohumeral size. The purpose of this study was to evaluate three-dimensional geometry of the glenohumeral joint in the normal Asian population and to clarify its morphologic features. Methods. Anthropometric analysis of the glenohumeral joint was performed using computed tomography scans of 160 normal shoulders from healthy volunteers in age from 20 to 40 years. Using OsiriX MD, Geomagic Studio, and AVIZO software, the dimensions of humeral head width, humeral head diameter, glenoid height, glenoid width, and glenoid diameter were analyzed three-dimensionally (Figure 1). In diameter analyses, the humeral head was assumed to be a sphere and the glenoid was to fit a sphere (Figure 2–3). Sex differences in height, humeral length, humeral head width, humeral head diameter, glenoid height, glenoid width, and glenoid diameter were compared using Mann-Whitney U tests. The correlations between sides and among the respective parameters in the glenohumeral dimensions were evaluated with Spearman rank correlation tests. The significance level was set at 0.05 for all analyses. Results. Average height and humeral length of the volunteers were 164.7 ± 9.7 cm and 29.1 ± 1.8 cm respectively. The normal Asian glenohumeral joint has average humeral head width of 41.4 ± 3.7 mm, humeral head diameter of 42.9 ± 3.6 mm, glenoid height of 31.5 ± 2.8 mm, glenoid width of 23.1 ± 2.4 mm, and glenoid diameter of 62.0 ± 6.8 mm. The humeral head and glenoid were significantly larger in males than in females (p<0.001 in all analyses). The average radius difference between the glenoid and the humeral head was 9.6 ± 2.8 mm, and there was no sex difference (p=0.359). The average ratio of the glenoid radius to the humeral head radius was 144.9% ± 12.2%, and the ratio was significantly larger in females than in males (p=0.026). The glenohumeral size was well correlated between the two sides, and there were direct correlations among the heights, humeral length, humeral head size, and glenoid size (p<0.001 in all analyses). Conclusions. The present study revealed that the values of glenohumeral dimensions were uniform in both males and females with a strong correlation between the dominant shoulder and the nondominant shoulder. Since there are direct correlations among height, humeral length, and the size of the glenohumeral joint, we can also predict the glenohumeral size of patients from their respective heights. The present results would be useful to determine the size of implants and to improve clinical outcomes of shoulder arthroplasty for glenohumeral joints of Asian patients. The size of the Asian glenohumeral joint was obviously smaller than that reported in the past literature including black and Caucasian populations. Some shoulder prostheses that are designed in Europe or America and are widely used worldwide could be oversized for small females

A computer-assisted method of preoperative planning was used to create virtual models of the deformed distal end of the radius after malunion of a fracture. By comparison with a similar model of the uninjured wrist, values were calculated for the angles and lengths to be corrected by osteotomy. Shifts of the distal fragment were analysed for 33 deformed wrists, 27 of which underwent corrective osteotomy and bone grafting. In more than half the cases there was dorsal or volar shift of 3 mm or more. The accuracy of the correction was measured by comparing the three-dimensional models before and after osteotomy with the model of the normal wrist. The volar and ulnar inclination angles of the articular surface of the radius and the radial length were regularly restored to normal

Introduction. Histology remains the gold standard in morphometric and pathological analyses of osteochondral tissues in human and experimental bone and joint disease. However, histological tissue processing is laborious, destructive and only provides a two-dimensional image in a single anatomical plane. Micro computed tomography (μCT) enables non-destructive three-dimensional visualization and morphometry of mineralized tissues and, with the aid of contrast agents, soft tissues. In this study, we evaluated phosphotungstic acid-enhanced (PTA) μCT to visualize joint pathology in spine osteoarthritis. Methods. Lumbar facet joint specimens were acquired from six patients (5 female, age range 31–78) undergoing decompression surgery. Fresh osteochondral specimens were immediately fixed in formalin and scanned in a benchtop μCT scanner (65 kV, 153 mA, 25 μm resolution). Subsequently, samples were completely decalcified in 5% formic acid, equilibrated in 70% ethanol and stained up to ten days in 1% PTA (w/v) in 70% ethanol. PTA-stained specimens were scanned at 70 kV, 140 mA, 15 μm resolution. Depth-dependent analysis of X-ray attenuation in cartilage tissues was performed using ImageJ. Bone structural parameters of undecalcified and PTA-stained specimens were determined using CT Analyser and methods were compared using correlation and Bland-Altman analysis. Results. The maximal penetration depth of PTA in decalcified facet joint was 5 mm. Bone tissue showed strong and uniformly distributed X-ray attenuation, while mild to moderate and differentially distributed attenuation was observed in articular cartilage and subchondral marrow spaces. Measurements of bone volume (r=0.90, p=0.01) and bone surface (r=0.95, p=0.004) were strongly correlated between undecalcified and PTA-stained samples. Compared with PTA-stained samples, measurements in undecalcified specimens were consistently higher (∼14%). PTA-enhanced μCT visualization of cartilage tissues enabled the identification of individual chondrocytes and their pericellular microenvironment (chondrons). Owing to loss of collagen lower X-ray attenuation was observed in the middle and deep cartilage layers at the central, but not peripheral, regions of the degenerated facet joint specimens. Depth-dependent analysis of PTA-staining intensity suggested that the extent of collagen loss in articular cartilage might correlate with the thickness of the subchondral cortical plate. Conclusion. PTA-enhanced μCT is a low-cost, non-toxic and highly feasible method for ex vivo 3D-visualization of osteochondral pathology in human osteoarthritis. The method enables bone morphometric analysis, as well as collagen distribution in all anatomical planes. Contrast enhanced μCT has several applications in bone and osteoarthritis research including 3D histopathological grading, tissue stratification, and imaging and analysis of aberrant collagen metabolism in osteochondral disease

Purpose: The mechanical function and strain behavior of the knee meniscus is not fully understood, due to multiple tissues with disparate properties, as well as complex contact patterns and intricate loading mechanisms. More comprehensive understanding of joint mechanics may contribute to improved treatment options for patients with injuries and osteoarthritis. There is very limited information available on the 3D strain of the intact meniscus. The objective of this work was to use mCT with copper microsphere markers to quantify three-dimensional strain of the meniscus under physiologic loading. Method: Two healthy fresh frozen ovine knee specimens were harvested. Copper microspheres (0.5mm) were injected into anterior and posterior tetrahedral clusters in the medial meniscus using 20-gauge hypodermic needles. Needle cavities were sealed with ovine tendon tissue. Joints were loaded to 100% body weight in a 4 DOF CT-compatible pneumatically-driven device with flexion angles ranging from 62–98°. Images were acquired with an eXplore Locus Ultra mCT scanner and reconstructed with commercial software. A time series of images were acquired with the joint unloaded, during static loading, and at a reduced load (25% BW). Results: The average maximum principle strains in the anterior element of the two specimens at 62o of flexion increased by 21% during loading and decreased by 13% during unloading. The maximum principle strains were 28% larger in the anterior element than the posterior. The strains in the anterior element decreased by 6.5% with time following load application, and decreased by 16% with load reduction, yielding relatively low residual strain. Strains were 2% larger in the anterior portion with larger flexion angles. Conclusion: The objective of this work was to develop a reliable method for quantifying 3D strains in the meniscus. Results support the notion that mCT imaging with copper microspheres in the meniscus may be a viable technique for more comprehensive 3D strain analysis. The relatively low residual strains measured in this study indicate that copper microspheres are stable markers in this application. This technique may be useful in directing future studies aimed at understanding the impact of meniscal pathologies and the success of repair techniques

Objective. Computed tomography based three-dimensional surgical preoperative planning (3D-planning) has been expanded to achieve more precise placement of knee and hip arthroplasties. However, few reports have addressed the utility of 3D-planning for the total elbow arthroplasty (TEA). The purpose of this study was to assess the reliability and precision of 3D planning in unlinked TEA. Methods. Between April 2012 and April 2014, 17 joints in 17 patients (male 4, female 13) were included in this study. Sixteen patients were rheumatoid arthritis and one was osteoarthritis and the average age at the time of the procedure was 61 years (range 28–88). Unlinked K-NOW total elbow system (Teijin-Nakashima Medical. Co. Ltd.) was used in all cases and 3D planning was performed by Zed View (Lexi.Co.). After the appropriate size and position of the prosthesis were decided on the 3D images [Figure 1], the position of the bone tunnel made for the insertion of humeral and ulnar stem was recorded on axial, sagittal, and coronal plane (4 point measurements for humerus, and 6 points for ulna, See Figure 2). After the elbow was exposed via a posterior approach, bone resection and reaming was performed according to the 3D planning. The surgeon took an appropriate adjustment to align the prosthesis properly during the surgery. The final position of the stem insertion was recorded immediately prior to set the prostheses. We analyzed the accuracy of stem size prediction, the correlation between preoperative and final measurements, and postoperative complications. Results. The sizes of humeral stems and ulnar stems were estimated exactly in 70% (12/17) and 94 % (16/17) of all cases, respectively. All of the stem sizes were estimated accurately within one size. There was a strong correlation between the preoperative measurements around stem insertion and final position of the humerus with the correlation coefficient of 0.96–0.99, whereas the correlation was varied widely 0.48–0.97 for the ulna stem. The mean error in 3D orientation of the stem position was 0.56 mm for the humeral stem and 1.03 mm for the ulnar stem. There were no technical difficulties related to use of 3D-planning and the prostheses were properly placed in 16 cases, however posterior penetration of the ulnar stem occurred in 1 case. Conclusion. This study demonstrated the reliability and precision of preoperative 3D planning for unlinked TEA. Proper positioning of the prosthesis is extremely important to prevent maltracking and instability since postoperative instability has been a major complication of the unlinked TEA. This technique will potentially reduce the postoperative complications

Introduction: Three dimensional preoperative planning for each patient has been done in our institution. Anatomical designs of prosthesis are necessary to realize primary stability. The purpose of this study is to visualize the area which concerns about initial stability and load transfer post-operatively. Methods: A preoperative three-dimensional planning based on CT-scan data was performed. Two different contour prostheses (Versys and Revelation) were studied for each patient. Distance from central axis of the stem to inside wall of the femoral cortex (A) and distance from central axis of the stem to the surface of the stem (B) were measured. We defined B/A as cortex-stem ratio and mapped it on the surface of the stem like contour lines. Results: Cortex-stem ratio of Versys stem of proximal femur indicated over 90% at medial, but no more than 70% at anterior, posterior and lateral. In a circumference of distal stem, that ratio was high. On the contrary, cortex-stem ratio of Revelation represented 90~100% at medial and lateral,85~95% at anterior portion. Discussion: High rate region of cortex-stem ratio represent a great difference between Versys stem and Revelation stem. These region participate in primary fixation and lord transport to femoral cortex. Preoperative three-dimensional mapping is useful technique to better understand the relative position between the stem and the femur, to evaluate which regions were concerned in initial stability after operation and lord transfer later. The visualized result can also suggest the surgeons where and how to prepare the canal efficiently for each design of the stems

Introduction. Preoperative planning is an essential procedure for successful total hip arthroplasty. Many studies reported lower accuracy of two-dimensional analogue or digital templating for developmentally dysplastic hips (DDH). There have been few studies regarding the utility of three-dimensional (3D) templating for DDH. The aim of the present study is to assess the accuracy and reliability of 3D templating of cementless THA for hip dysplasia. Methods. We used 86 sets of 3D-CT data of 84 patients who underwent consecutive cementless THA using an anatomical stem and a rim-enlarged cup. There were six men and 78 women with the mean age of 58 years. The diagnosis was developmental dysplasia in 70 hips and osteonecrosis in 14 hips and primary osteoarthritis in 2 hips. There were 53 hips in Crowe group I, 11 hips in Crowe group II and 6 hips in Crowe group III. Each operator performed 3D templating prior surgery using a planning workstation of CT-based navigation system. Planned-versus-achieved accuracy was evaluated. The templating results were categorized as either exact size or +/− 1 size of implanted size. To assess the intra- and inter-planner reliabilities, 3D templating was performed by two authors blinded to surgery twice at an interval of one month. Kappa values were calculated. The accuracy and the intra- and inter-planner reliabilities were compared between the DDH group (70 hips) and the non DDH group (16 hips). Results. There was no significant difference in accuracy of component sizes between the DDH group and the non-DDH group. The accuracy of templating for cup sizes was 76 % for DDH and 75 % for non-DDH group (p=0.95). If accuracy was expanded to include all cups within one size of the implanted size, the accuracy was 97 % and 94 %, respectively (p=0.51). The accuracy of templating for stem sizes was 60 % for the DDH group and 75 % for the non-DDH group (p=0.27). The accuracy within 1 size was 99 % and 94 %, respectively (p=0.25). Regarding intra-planner reliability, mean kappa value for the cup size was 0.67 in the DDH group and 0.81 for the non-DDH group (p=0.18). Mean kappa value for the stem size was 0.64 in the DDH group and 0.79 for the non-DDH group (p=0.18). There were no significant differences in intra-planner reliability between the DDH and non-DDH group. Regarding inter-planner reliability for the cup size, mean kappa value was 0.33 in the DDH group and 0.37 in the non-DDH group (p=0.14). Mean kappa value for the stem size was 0.46 in the DDH group and 0.69 in the non-DDH group (p=0.07). There were no significant differences in inter-planner reliability between the DDH and non-DDH group. Conclusion. The 3D templating for cementless THA was accurate for hip dysplasia. Intra- and inter-planner reliabilities of the 3D templating were comparable with those of other primary diagnosis, while intra-planner reliability of cup sizes was fair regardless of diagnosis

Introduction: The use of hard-on-hard hip prostheses has highlighted specific problems like the “stripe-wear” and the squeaking. Many authors have related these phenomena to a micro-separation between the cup and the head. The goal of the study was to model the hip kinematics under micro-separation regime in order to develop a computational simulator for total hip prosthesis including a joint laxity, and to use it to perform a sound analysis. Method: A three-dimensional model of the Leeds II hip simulator was developed on ADAMS. ®. software. A spring was used to introduce a controlled micro-separation (less than 500 microns) during the swing phase of the walking cycle. The increase of the load during the stance phase induced a relocation of the head in the cup. Values of the medial-lateral separation predicted from the model were compared to experimental data measured using a LVDT of less than 5 microns precision. Theoretical wear path predicted from the model was compared to the literature data. The frequencies of the vibratory phenomena were determined, using the Fourier transformation. Results: There was an excellent correlation between the theoretical prediction and the experimental measurement of the medial-lateral separation during the walking cycle (0.92). Edge-loading contact occurred during 57% of the cycle according to the model and 47% according to the experimental data. Velocity and acceleration were increased during the relocation phase in a chaotic manner, leading to vibration. The contact force according to the model had also a chaotic variation during the micro-separation phase, suggesting a chattering movement. Fourier transformation showed many frequencies in the audible area. Discussion: A three-dimensional computational model of the kinematics of the hip after total replacement was developed and validated with an excellent precision under microseparation. It highlighted possible explanations for the squeaking that may occur during either relocation phase or edge loading

Accurate comparison of outcomes regarding various surgical options in knee arthroplasty calls for an improved method of joint line analysis that takes into account the preoperative cartilage thickness. Current methods for measuring joint lines have limitations. This is commonly done on anteroposterior or lateral radiographs, by measuring landmarks defining the joint line with reference to a common landmark such as the fibular head, the medial femoral epicondyle or the tibial tuberosity. These radiographic methods are unable to measure important differences between the medial and lateral joint lines. Furthermore, poor accuracies due to sensitivity to patient and X-ray beam positions have been reported for these methods. The aim of this study was to introduce a method to measure the joint line shift for any desired flexion angle of the joint by taking into account the cartilage thickness on both the medial and lateral sides and under weightbearing conditions. The suggested method inludes four steps (Figure 1): a) preoperative joint imaging and 3D-2D matching between pre-operative 3D models and bi-planar 2D images; b) postoperative joint imaging and 3D-2D matching between implant 3D models and 3D models of the bones to bi-planar 2D images; c) superimposition of the locations of the implant components on the preoperative joint positions to determine changes in the joint line on the medial and lateral sides of the joint for both extension and flexion positions. To determine the tibial joint line, the three-dimensional model of the polyethylene inlay was added to the metal tray according to the design of its locking mechanism. Two-dimensional cross-sectional slices of the combined bone and implant models were obtained perpendicular to the tibial tray and passed through the most distal points of the medial and lateral condyles of the femoral component. Joint line shift was measured as the distance between the most distal point on the condyle of the femoral component and the most proximal point on the articular surface of the tibial polyethylene in the direction normal to the mediolateral edge of the tibial tray in the cross-sectional slice. The method was tested on six cadaveric specimens. The joint line shift, measured using the new method, was in the range of −0.2 to 1.3 mm on average (SD=1.3 to 3.8 mm for medial and lateral, flexion and extension). This was significantly different (p≤0.01) from the results of a previously post-op based registration method which did not account for the cartilage thickness. These results demonstrate the importance of the preoperative joint space when analyzing the joint line, and highlight the utility of the newly introduced method. The method introduced in this study combines the preoperative and postoperative images to provide accurate 3D measures of joint line shifts. The method incorporates cartilage thickness in the analysis and is insensitive to patient and X-ray beam position, and can be applied at any flexion angle of the knee. The method yields much smaller measures of joint line shift than a previous approach, which suggests that the previous method may have overestimated joint line shift substantially

The use of hard-on-hard hip prostheses has highlighted specific problems like the “stripe-wear” and the squeaking. Many authors have related these phenomena to a micro-separation between the cup and the head. The goal of the study was to model the hip kinematics under micro-separation regime in order to develop a computational simulator for total hip prosthesis including a joint laxity, and to use it to perform a sound analysis. A three-dimensional model of the Leeds II hip simulator was developed on ADAMS® software. A spring was used to introduce a controlled micro-separation (less than 500 microns) during the swing phase of the walking cycle. The increase of the load during the stance phase induced a relocation of the head in the cup. Values of the medial-lateral separation predicted from the model were compared to experimental data measured using a LVDT of less than 5 microns precision. Theoretical wear path predicted from the model was compared to the literature data. The frequencies of the vibratory phenomena were determined, using the Fourier transformation. There was an excellent correlation between the theoretical prediction and the experimental measurement of the medial-lateral separation during the walking cycle (0.92). Edge-loading contact occurred during 57% of the cycle according to the model and 47% according to the experimental data. Velocity and acceleration were increased during the relocation phase in a chaotic manner, leading to vibration. The contact force according to the model had also a chaotic variation during the micro-separation phase, suggesting a chattering movement. Fourier transformation showed many frequencies in the audible area. A three-dimensional computational model of the kinematics of the hip after total replacement was developed and validated with an excellent precision under micro separation. It highlighted possible explanations for the squeaking that may occur during either relocation phase or edge loading

To confirm whether developmental dysplasia of the hip has a risk of hip impingement, we analysed maximum ranges of movement to the point of bony impingement, and impingement location using three-dimensional (3D) surface models of the pelvis and femur in combination with 3D morphology of the hip joint using computer-assisted methods. Results of computed tomography were examined for 52 hip joints with DDH and 73 normal healthy hip joints. DDH shows larger maximum extension (p = 0.001) and internal rotation at 90° flexion (p < 0.001). Similar maximum flexion (p = 0.835) and external rotation (p = 0.713) were observed between groups, while high rates of extra-articular impingement were noticed in these directions in DDH (p < 0.001). Smaller cranial acetabular anteversion (p = 0.048), centre-edge angles (p < 0.001), a circumferentially shallower acetabulum, larger femoral neck anteversion (p < 0.001), and larger alpha angle were identified in DDH. Risk of anterior impingement in retroverted DDH hips is similar to that in retroverted normal hips in excessive adduction but minimal in less adduction. These findings might be borne in mind when considering the possibility of extra-articular posterior impingement in DDH being a source of pain, particularly for patients with a highly anteverted femoral neck. Cite this article: Bone Joint J 2014;96-B:580–9

The use of stem cells in tissue engineering has emerged as a promising therapy for the repair of bone and cartilage defects. Targeted delivery of stem cells requires a substrate to maintain the cells at the repair site, as well as to provide the physical cues, such as mechanical strain, for encouraging differentiation and expression of the mature cell phenotype. The strains that will be generated in cells residing on the scaffold is dependent on the scaffold material, as well as both the fibre thickness and the fibre orientation in the scaffold. To encourage uniform bone matrix generation throughout the scaffold, it is desirable that the strain be uniformly distributed and that the internal pore architecture be precisely controlled to maximise media diffusion. This requires an optimised scaffold design and a manufacturing technique that allows for precise control over the scaffold’s internal architecture. Scaffold architecture was optimised by performing a series of finite element analyses (FEA) on computer aided design (CAD) models of Polycaprolactone (PCL) scaffolds. The mechanical properties of PCL were used to yield an accurate strain profile of scaffolds with different fibre orientations. Having determined the optimal scaffold geometry, PCL scaffolds were manufactured using a fibre deposition technique that yielded three-dimensional objects with this geometry. During manufacture, a PCL solution was extruded into a non-miscible solvent which precipitated out PCL fibres in repetitive layers. Of the geometries tested with FEA, a 90 degree rotation of adjacent layers with a 50% offset of parallel strands was found to provide the optimal strain distribution (60% increase in surface exposed to strain). Histomorphometry was used to assess the exact dimensions of the scaffold produced. Fibre spacing was found to be precisely controlled to 380 +/- 10 microns within the layers and the fibre thickness was controlled to 270 +/- 10 microns. This demonstrates that FEA can be used to predict the strain distribution of different CAD models and that the fibre deposition solvent extrusion technique can be used to accurately manufacture PCL scaffolds that match the desired architecture

A clinical and radiographic study was conducted on 97 total hip arthroplasties (79 patients) performed for congenital hip dislocation using three-dimensional custom cementless stem. The mean age was 48 years (17 to 72). The mean follow up was 123 months (83 to 182). According to Crowe, there were 37 class 1, 28 class 2, 13 class 3 and 19 class 4. The average lengthening was 25 mm (5 to 58 mm), the mean femoral anteversion 38.6° (2° to 86°) and the correction in the prosthetic neck −23.6° (71° to 13°). The average Harris hip score improved from 58 to 93 points. Six hips (6.2%) required a revision. The survival rate was 97.7% ± 0.3% at 13 years. Custom cementless stem allows anatomical reconstruction and good functional results in a young and active population with disturbed anatomy, while avoiding a femoral osteotomy

An anatomical cementless stem sometimes does not fit the femur of Japanese osteoarthritis (OA) patients due to deformity of the proximal femoral canal. In order to develop a new stem, we performed morphological analysis of 36 normal femora and 113 OA femora by using a computer aided design system and a three-dimensional canal fill ratio of anatomical stem was calculated. Thirty-six normal femora and 113 OA femora were reconstructed from 3D-CT data by using a computer aided design system. We analyzed each femur, and it became clear that there are 3 types of proximal femur in Japanese OA patients. In typeI, the configuration is the same as normal (42%). In typeII, the medial cortex is more steep (29%). In typeIII, the posterior cortex inclines anterior (26%). We chose 5 femora of the same size from each of the three types, and applied the anatomical stem of the most suitable size to each femur in the computer, we then calculated a three-dimensional canal fill ratio of the anatomical stem in the proximal portion of femoral canal. The mean canal fill ratio was 76.4% in typeI, 60.0% in typeII, and 57.2% in typeIII. The canal fill ratio in typeI was significantly higher than the other types. It is thought that to fill the proximal femoral canal with cementless stem is important to stabilize the stem and can lead to a good result. The anatomical stem fitted for the typeI, but did not fit for typeII and III, so we must consider developing a more suitable stem for typeII and typeIII

Although proximal tibia vara is physiologically and pathologically observed, it is difficult to measure the varus angle accurately and reproducibly due to inaccuracy of the radiograph because of rotational and/or torsional deformities. Since tibial coronal alignment in TKA gives influence on implant longevity, intra- or extra-medurally cutting guide should be set carefully especially in cases with severe tibia vara. In this context, we measured the proximal tibial varus angle by introducing 3D-coordinate system. Materials & Methods. Three-dimensional models of 32 tibiae (23 females, 9 males, 71.2 ± 7.8 y/o) were reconstructed from CT data of the patients undergoing CT-based navigation assisted TKA. Clinically relevant mid-sagittal plane is defined by proximal tibial antero-posterior axis and an apex of the tibial plafond. After the cross-sectional contours of the tibial canal were extracted, least-square lines were fitted to define the proximal diaphyseal and the metaphyseal anatomical axis. The proximal tibia vara was firstly investigated in terms of distribution of proximal anatomical axis exits at the joint surface. TVA1 and TVA2 were defined to be a project angle on the coronal plane between the metaphyseal tibial anatomical axis and the proximal diaphyseal anatomical axis, and that between the metaphyseal tibial anatomical axis and the tibial functional axis, respectively. The correlations of each angle with age and femoro-tibial angle (FTA) were also examined. Results. The proximal anatomical axis exits distributed 4.3 ± 1.7 mm medially and 17.1 ± 3.4 mm anteriorly. TVA1 and TVA2 were 12.5 ± 4.5°(4.4?23.0°) and 11.8 ± 4.4° (4.4?22.0°), respectively. The correlations of FTA with TVA1 (r=0.374, p<0.05) and TVA2 (r=0.439, p<0.05) were statistically significant. Discussion. This is the first study that analyses tibia vara in the 3D-algorythm and that investigates its correlations with FTA. In the coronal plane, proximal tibia was actually varus, and TVA varied substantially among patients and correlated with FTA. These data implicated that TVA was involved in the pathophysiology of osteoarthritic deformities, directly or indirectly. Also tibia vara should be considered while placing the instrument to cut proximal tibia to obtain optimal setting of the implant in TKA

We examined the relationship between the size of the femoral cam in femoroacetabular impingement (FAI) and acetabular pathomorphology to establish if pincer impingement exists in patients with a femoral cam. CT scans of 37 symptomatic impinging hips with a femoral cam were analysed in a three-dimensional study and were compared with 34 normal hips. The inclination and version of the acetabulum as well as the acetabular rim angle and the bony acetabular coverage were calculated. These measurements were correlated with the size and shape of the femoral cams. While the size of the femoral cam varied characteristically, the acetabular morphology of the two groups was similar in terms of version (normal mean 23° (. sd. 7°); cam mean 22° (. sd.  9°)), inclination (normal mean 57° (. sd. 5°); cam mean 56° (. sd. 5°)), acetabular coverage (normal mean 41% (. sd. 5%); cam mean 42% (. sd. 4%)) and the mean acetabular rim angle (normal mean 82° (. sd. 5°); cam mean 83° (. sd. 4°)). We found no correlation between acetabular morphology and the severity of cam lesion and no evidence of either global or focal over-coverage to support the diagnosis of ‘mixed’ FAI. The femoral cam may provoke edge loading but removal of any acetabular bearing surface when treating cam FAI might induce accelerated wear. Cite this article: Bone Joint J 2013;95-B:314–19

Non-invasive, in vivo measurement of the three-dimensional (3-D) motion of the tibiofemoral joint is essential for the study of the biomechanics and functional assessment of the knee. Real-time magnetic resonance imaging (MRI) techniques enable the measurement of dynamic motions of the knee with satisfactory image quality and free of radiation exposures but are limited to planar motions in selected slice(s). The aims of the current study were to propose a slice-to-volume registration (SVR) method in conjunction with dual-slice, real-time MRI for measuring 3-D tibiofemoral motion; and to evaluate its repeatability during passive knee flexion. Eight healthy young adults participated in the current study, giving informed written consent as approved by the Institutional Research Board. A 3-T MRI system (Verio, Siemens, Erlangen, Germany) incorporated with a neck matrix coil was used to collect the MRI data. A 3-D scanning using the VIBE sequence was used to collect the volumetric data of the knee at fully extended position (TR = 4.64 ms, TE = 2.3 ms, flip angle = 15°, in-plane resolution = 0.39 × 0.39 mm. 2. and slice thickness = 0.8 mm). A real-time MRI using the refocused radial FLASH sequence (TR = 4.3 ms, TE = 2.3 ms, flip angle = 20°, in-plane resolution = 1.0 × 1.0 mm. 2. , slice thickness = 6 mm) was used to acquire a pair of image slices of the knee at a frame rate of 3 fps during passive flexion. The volumetric MRI data sets were segmented for the femur and tibia/fibula to isolate the sub-volumes containing bone segments. A slice-to-volume registration method was then performed to determine the 3-D poses of the bones based on the spatial matching between sub-volume of the bones and the real-time image slices. The bone poses for all frames were used to calculate the rigid-body kinematics of the tibiofemoral joint in terms of the flexion/extension (FE), internal/external rotation (IR/ER), abduction/adduction (Abd/Add) and joint center translations along three anatomical axis of the tibia. The procedures were carried out five times for repeatability analysis. The standard deviation (SD) of the rigid-body kinematics for each frame from the five trials were calculated and then averaged across all frames to give quantitative measures of the repeatability of the kinematic variables. The repeatability analysis showed that the mean±SD of the averaged SD in FE, Abd/Add and IR/ER components across all subjects were 0.25±0.09, 0.46±0.13 and 0.77±0.16 degrees, respectively. The corresponding values for the joint translations in anterior/posterior, proximal/distal and medial/lateral directions were 0.21±0.04, 0.11±0.03 and 0.43±0.09 mm. An SVR method in conjunction with dual-slice real-time MRI has been successfully developed and its repeatability in measuring 3-D motion of the tibiofemoral joint evaluated. The results show that the proposed method is capable of providing rigid-body kinematics with sub-millimeter and sub-degree precision (repeatability). The proposed SVR method using real-time MRI will be a valuable tool for non-invasive, functional assessment of the knee without involving ionizing radiation, and may be further developed for joint stability assessment

Introduction. Currently, different techniques to evaluate biocompatibility of orthopaedic materials, including two-dimensional (2D) cell culture for metal and ceramic wear debris and floating 2D surfaces or three-dimensional (3D) agarose gels for UHMWPE wear debris, are used. We have developed a single method using 3D agarose gels that is suitable to test the biocompatibility of all three types of wear debris simultaneously. Moreover, stimulation of the cells by wear particles embedded in a 3D gel better mimics the in vivo environment. Materials and Methods. Clinically relevant sterile UHMWPE and CoCr wear particles were generated using methodologies described previously [1,2]. Commercially available nanoscale and micron-sized silicon nitride (Si. 3. N. 4. ) particles (<50 nm and <1 μm, Sigma UK) were sterilised by heat treatment for 4h at 180°C. Agarose-particle suspensions were prepared by mixing warm 2% (w/v) low-melting-point agarose solution with the particles dispersed by sonication in DMEM culture media. The suspensions were then allowed to set at room temperature for 10 min in 96 well culture plates. Sub-confluent L929 murine fibroblasts were cultured on the prepared gels for up to 6 days in 5% (v/v) CO. 2. at 37°C. After incubation, the viability of cells was measured using the ATP-lite assay. The results were expressed as mean ± 95% confidence limits and the data was analysed using one-way ANOVA and Tukey-Kramer post-hoc analysis. Results and Discussion. The gels were observed to ensure uniform distribution of particles and migration of cells into the gel. No significant reduction in viability was observed for nanoscale and micron-sized Si. 3. N. 4. particles at low doses (0.5 μm. 3. per cell) and high doses (50 μm. 3. per cell), or for UHMWPE wear debris at high doses (100 μm. 3. per cell) [Figure1]. Moreover, the viability was significantly reduced for high doses of CoCr wear debris (50 μm. 3. per cell) and the positive control, camptothecin (2 μg.ml. −1. ) at day 6 [Figure1]. These results are consistent with the literature [2,3] and therefore validate our 3D agarose cell culture method for comparing cytotoxicity of polymer, metal and ceramic particles in a single assay, simultaneously. Conclusion. Biocompatibility ofpolymer, metal and ceramic wear debris can be tested simultaneously by using 3D particle embedded agarose gels. Acknowledgements. The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. GA-310477 LifeLongJoints

We obtained medial and lateral subchondral cancellous bone specimens from ten human postmortem proximal tibiae with early osteoarthritis (OA) and ten normal age- and gender-matched proximal tibiae. The specimens were scanned by micro-CT and the three-dimensional microstructural properties were quantified. Medial OA cancellous bone was significantly thicker and markedly plate-like, but lower in mechanical properties than normal bone. Similar microstructural changes were also observed for the lateral specimens from OA bone, although there had been no sign of cartilage damage. The increased trabecular thickness and density, but relatively decreased connectivity suggest a mechanism of bone remodelling in early OA as a process of filling trabecular cavities. This process leads to a progressive change of trabeculae from rod-like to plate-like, the opposite to that of normal ageing. The decreased mechanical properties of subchondral cancellous bone in OA, which are due to deterioration in architecture and density, indicate poor bone quality

Objects: We have studied knee morphology using 3DCT considering the bone cutting surface in Total Knee Arthroplasty (TKA in Japan. Subjects were 50 knees in 49 with knee disorders, consisting of 20 knees in 20 men and 30 knees in 29 women. The age range was 16–77 year old (the mean age 52.2). Method: The image of a patient’s knee joint was taken by three-dimensional perspective imaging device (SIEMENS, ARCADIS) before surgery, and it was structured with the three-dimensional computer software K.G.T, INTAGE Realia Professional to measure the knee joint configuration. In the measured site with assumption of the bone cutting surface of the femur side in TKA, the valgus angle of femur was °to the bone axis and the maximum transverse diameter and the maximum anteroposterior diameter of the external condyle were measured at the femur side 8 mm proximal to the external condyle, and the tibial side was vertical to the bone axis and the maximum anteroposterior diameter of the internal and external condyles were measured at the tibial side 2 mm distal to the interior joint surface. The ratio of the anteroposterior diameter and the transverse diameter was computed by these measurements. Result: The average measurements of the femur were 70.82mm of the transverse diameter, 51.2mm of the anteroposterior diameter, and 0.73 of the ratio of the anteroposterior diameter and the transverse diameter. The average measurements of the tibia were 72.5mm of the transverse diameter, 54.4mm of the anteroposterior diameter of the interior condyle, 46.7mm of the anteroposterior diameter of the exterior condyle, and 0.75 and 0.64 of the ratio of the anteroposterior diameter and the transverse diameter of the interior and exterior condyles, respectively. The measurements of the femur were bigger in any sites of men than women, and the transverse diameter was bigger, the anteroposterior diameter tended to be smaller. The transverse diameter did not clearly correlate with the ratio of the anteroposterior diameter and the transverse diameter at the tibial side, and different correlations were shown between men and women respectively. Discussion: At the femur side, a Japanese knee was flatter than a Westerner’s knee just like the previous reports in Japan. The knee is bigger, the knee tends to become flatter, and men are more likely to have the tendency than women. At the tibia side, there were differences for correlation of the flat level between men and women, and it suggested the potential sex difference. Conclusion: The measurement with 3DCT is easy-to-use, and the variation is small compared to an actual measurement value. We want to put it to use for implant design in references to these measurements for the future

A functional total knee replacement has to be well aligned, which implies that it should lie along the mechanical axis and in the correct axial and rotational planes. Incorrect alignment will lead to abnormal wear, early mechanical loosening, and patellofemoral problems. There has been increased interest of late in total knee arthroplasty with robot assistance. This study was conducted to determine if robot-assisted total knee arthroplasty is superior to the conventional surgical method with regard to the precision of implant positioning. Twenty knee replacements of ten robot-assisted and another ten conventional operations were performed on ten cadavers. Two experienced surgeons performed the surgery. Both procedures were undertaken by one surgeon on each cadaver. The choice of which was to be done first was randomized. After the implantation of the prosthesis, the mechanical-axis deviation, femoral coronal angle, tibial coronal angle, femoral sagittal angle, tibial sagittal angle, and femoral rotational alignment were measured via three-dimensional CT scanning. These variants were then compared with the preoperative planned values. In the robot-assisted surgery, the mechanical-axis deviation ranged from −1.94 to 2.13° (mean: −0.21°), the femoral coronal angle ranged from 88.08 to 90.99° (mean: 89.81°), the tibial coronal angle ranged from 89.01 to 92.36° (mean: 90.42°), the tibial sagittal angle ranged from 81.72 to 86.24° (mean: 83.20°), and the femoral rotational alignment ranged from 0.02 to 1.15° (mean: 0.52°) in relation to the transepicondylar axis. In the conventional surgery, the mechanical-axis deviation ranged from −3.19 to 3.84°(mean: −0.48°), the femoral coronal angle ranged from 88.36 to 92.29° (mean: 90.50°), the tibial coronal angle ranged from 88.15 to 91.51° (mean: 89.83°), the tibial sagittal angle ranged from 80.06 to 87.34° (mean: 84.50°), and the femoral rotational alignment ranged from 0.32 to 4.13° (mean: 2.76°) in relation to the transepicondylar axis. In the conventional surgery, there were two cases of outlier outside the range of 3° varus or valgus of the mechanical-axis deviation. The robot-assisted surgery showed significantly superior femoral-rotational-alignment results compared with the conventional surgery (p=0.006). There was no statistically significant difference between robot-assisted and conventional total knee arthroplasty in the other variants. All the variants were measured with high intraobserver and interobserver reliability. In conclusion, Robot-assisted total knee arthroplasty showed excellent precision in the sagittal and coronal planes of the three-dimensional CT. Especially, better accuracy in femoral rotational alignment was shown in the robot-assisted surgery than in the conventional surgery despite the fact that the surgeons who performed the operation were more experienced and familiar with the conventional surgery than with robot-assisted surgery. It can thus be concluded that robot-assisted total knee arthroplasty is superior to the conventional total knee arthroplasty

Background. A high precision of three-dimensional (3D) computerised planning of THA was recently reported. However, there is no comparative study analysing the value of 3D planning comparatively to the planning made on X-rays using 2D templates. Material and method. A prospective comparative randomised study was carried out from 2008 to 2009, and included 2 groups of 32 patients who underwent THA for primary osteoarthritis. One surgeon performed all the procedures using a direct anterior approach. In one group, the planning was made on calibrated X-Rays using 2D templates. In the other group, a 3D planning was performed based on CT-scan using the Hip-Plan software. Post operatively, the final hip anatomy was analysed on X-Rays for the 2D group and on CT-scan for the 3D group. Results. In the 3D group, the duration of the surgical procedure was 18% shorter and the bleeding was 34% lower. The prediction rate of the stem and the cup sizes were respectively of 100% and 97% in the 3D group. In the 2D group, these rates were 43%. When combining both components, the prediction rate was 97% in the 3D group and 16% in the 2D group. The center of rotation, the femoral off-set and the length were restored with a twice higher precision in the 3D group. Discussion. This higher precision was probably due to the accurate analysis of the hip anatomy, the problems that may be encountered were detected before surgery. Clinical benefits for the patients were also proved. This technique is now our gold standard procedure

Aim. The aim of this study is to evaluate the effect of three-dimensional (3D) simulation with 3D planning software ZedKnee® (ZK) in total knee arthroplasty (TKA). Materials and methods. The participants in this study were all TKA patients whose operations were simulated by using ZK. The alignment of all components was evaluated with the ZK valuation software in postoperative computer tomography. Thirty patients (43 knees) met the inclusion criteria. 6 patients were male and 24 patients were female. The mean age of the 30 patients was 72 years old. Diagnoses for surgery were: osteoarthritis- 40 knees, rheumatoid arthritis- 2 knees and osteonecrosis- 1 knee. TKA was performed using the measured resection technique. The distal femur axis where the intramedullary rod would be inserted was drawn manually on the 3D image. Then, the angle between the distal femoral axis and the mechanical axis was measured. The rotational angles of the femoral components were determined from the automatically calculated angle between the posterior condylar axis and the surgical epicondylar axis (SEA) by using ZK. The ZK data used during the operation was the posterior condylar angle, the angle between the distal femoral axis and the mechanical axis and implant size. Results. The angle in coronal plane between the 3D mechanical axis and the distal femoral axis in preoperative planning ranged between 3 degrees and 11 degrees, mean 6.7 (SD 2.2) degrees. The postoperative femoral component alignment was on average 0.7 (SD 1.3) degrees in varus. Outlier of more than 3 degrees in coronal alignment was recognized in 3 cases (7%). The mean posterior condylar angle in preoperative planning was 3.8 (SD 1) degrees. The postoperative femoral component alignment was on average 1.5 (SD 1.6) degrees in external rotation to surgical epicondylar axis. Outlier of more than 3 degrees in rotational alignment was recognized in 6 cases (14%). The concordance rate between the preoperative planning size and the intraoperative selective size was 91%. Discussion. Some errors may be observed in the preoperative TKA X-ray planning, because of the rotational position of the femur while having the X-ray taken or angle of the X-ray beam. Kanekasu et al reported the measurement of the condylar twist angle during the X-ray and it was relatively correct compared with the measurement during CT. Max 1.9 degrees error occurred in the measurements using X-rays. It appeared that preoperative planning using CTs was more accurate than using X-rays. Conclusion. Femoral components with 3D simulation using ZK were fixed perpendicularly against the mechanical axis and parallel to the surgical epicondylar axis with high accuracy. We considered that the ZK 3D simulation in TKA is useful for the accurate alignment of femoral components

Abstract

Introduction. Osteoporosis (OP), osteoarthrosis (OA), and rheumatoid arthritis (RA) are the most common age-related degenerative bone diseases, and major public health problems in terms of enormous amount of economic cost. RA is considered as a major cause of secondary osteoporosis. At late stage, OP often leads to skeletal fractures, and OA and RA result in severe joint disability. Over the last a few decades, much significant research on the properties has been carried out on these diseases, however, a detailed comparison of the microarchitecture of cancellous bones of these diseases is not available. In this study, we investigated three-dimensional (3-D) microarchitectural properties of OP, OA and RA cancellous bone. We hypothesized that there were significant differences in microarchitecture among OP, OA and RA bone tissues that might lead to different bone quality. Materials and Method. Twenty OP, fifty OA, and twelve RA femur heads were harvested from patients undergone total hip replacement surgery. Cubic cancellous bone samples (8∗8∗8 mm3) were prepared and scanned with a high resolution microtomographic system (vivaCT 40, Scanco Medical AG., Brüttisellen, Switzerland). Then micro-CT images were segmented using individual thresholds to obtain accurate 3-D data sets. Detailed microarchitectural properties were evaluated based on novel unbiased, model-free 3-D methods. For statistical analysis, one-way ANOVA was used, and a p<0.05 was considered significant. Results. Significant differences in the microarchitecture of cancellous bone were observed among the OP, OA and RA groups. Compared with the other groups, OP cancellous bone had lowest density, thinner, typical rod-like structure and less connectivity (all p<0.01). Interestingly, there were no significant differences in the microarchitectural properties measured between the OA and RA cancellous bones. Both OA and RA cancellous bones had significant higher bone volume fraction and were thicker, typical plate-like structure compared with the OP group (all p<0.01), even though there was clearly bone erosion observed in RA cancellous bone. Discussion. Quantification of the alterations in bone properties and quality will help to gain more insights into the pathogenesis of degenerative bone diseases and to target and develop novel approaches for the intervention and treatment, and for the design, fixation and durability of total joint prosthesis. Our study demonstrated that there were significant differences in the microarchitecture of the OP, OA and RA femur head cancellous bone. The OA and RA cancellous bone had similar bone density and microarchitecture despite apparent bone erosion in the RA cancellous bone. These results from femur head did not support the traditional notion that RA and OP had similar low bone density. Thus, whether femur head bone tissues from these diseases have similar bone collagen, mineral and mechanical properties, more importantly bone quality, should be clarified in the future

Purpose: Patellar bracing is a common, mechanical-based treatment strategy for patellofemoral osteoarthritis (OA). It is thought that the brace corrects patellar tracking, however, this correction has not been quantified in the OA population. Through advances in magnetic resonance imaging (MRI), we can now assess patellar tracking in three-dimensions. Method: We assessed three-dimensional patellar tracking in ten subjects with symptomatic radiographic patellofemoral knee OA using a validated, quasi-static, MRI-based method. Four conditions were studied:. no knee brace, no load,. no knee brace, 15% bodyweight (BW) load,. knee brace, no load,. knee brace, 15% BW load. Patellar tracking (flexion, spin and tilt; proximal, lateral and anterior translation) was assessed. Comparisons were made at 1° increments over the coincidental range of knee flexion between the no-brace and brace conditions, at no load and 15% BW load, using a paired t-test with Bonferroni correction. Results: All subjects (7 female, 3 male, 60.9±1.3 yrs, 89.5±19.3 kg) had radiographic lateral patellofemoral OA and seven had concomitant tibiofemoral OA (KL grade≥2). Under no load, the brace extended (mean=2.7°, CI=[2.4°, 2.9°], P< 0.001) and medially tilted (mean=−1.4°, CI=[−1.6°, −1.2°], P< 0.001) the patellae and shifted them distally (mean=0.8mm, CI=[0.6mm, 0.9mm], P< 0.001), medially (mean=0.5mm, CI=[0.5mm, 0.6mm], P< 0.001) and posteriorly (mean=0.6mm, CI=[0.5mm, 0.6mm], P< 0.001). Under 15% BW load, the brace extended the patella (mean=2.4°, CI=[2.1°, 2.8°], P< 0.001) and shifted them distally (mean=1.3mm, CI=[1.1mm, 1.4mm], P< 0.001), medially (mean=0.8mm, CI=[0.7mm, 0.9mm], P< 0.001) and posteriorly (mean 0.6mm, CI=[0.5mm, 0.7mm], P< 0.001). Conclusion: The brace extended the patellae for both loading conditions, suggesting that patellar flexion/extension is restricted by the brace. The brace tilted the patellae medially under no load only, suggesting when the quadriceps are active (15% BW load) the brace has little effect for tilt. While the effect of bracing on patellar tracking may appear small, the differences are of similar magnitude to those observed between normals and patients with patellofemoral pain, suggesting that braces may produce clinically significant changes in patellar tracking

In pre-operative planning for total hip arthroplasty (THA), femoral offset (FO) is frequently underestimated on AP pelvis radiographs as a result of inaccurate patient positioning, imprecise magnification, and radiographic beam divergence. The aim of the present study was to evaluate the reliability and accuracy of predicting three-dimensional (3-D) FO as measured on computed tomography (CT) from measurements performed on standardised AP pelvis radiographs. In a retrospective cohort study, pre-operative AP pelvis radiographs and corresponding CT scans of a consecutive series of 345 patients (345 hips, 146 males, 199 females, mean age 60 (range: 40-79) years, mean body-mass-index 27 (range: 29-57) kg/m2) with primary end-stage hip osteoarthritis were reviewed. Patients were positioned according to a standardised protocol and all images were calibrated. Using validated custom programmes, FO was measured on corresponding AP pelvis radiographs and CT scans. Inter- and intra-observer reliability of the measurement methods were evaluated using intra-class correlation coefficients (ICC). To predict 3-D FO from AP pelvis measurements, the entire cohort was randomly split in two groups and gender specific linear regression equations were derived from a subgroup of 250 patients (group A). The accuracy of the derived prediction equations was subsequently assessed in a second subgroup of 100 patients (group B). In the entire cohort, mean FO was 39.2mm (95%CI: 38.5-40.0mm) on AP pelvis radiographs and 44.6mm (95%CI: 44.0-45.2mm) on CT scans. FO was underestimated by 14% on AP pelvis radiographs compared to CT (5.4mm, 95%CI: 4.8-6.0mm, p<0.001) and both parameters demonstrated a linear correlation (r=0.642, p<0.001). In group B, we observed no significant difference between gender specific predicted FO (males: 48.0mm, 95%CI: 47.1-48.8mm; females: 42.0mm, 95%CI: 41.1-42.8mm) and FO as measured on CT (males: 47.7mm, 95%CI: 46.1-49.4mm, p=0.689; females: 41.6mm, 95%CI: 40.3-43.0mm, p=0.607). The results of the present study suggest that femoral offset can be accurately and reliably predicted from AP pelvis radiographs in patients with primary end-stage hip osteoarthritis. Our findings support the surgeon in pre-operative templating and may improve offset and limb length restoration in THA without the routine performance of CT

Long-term biological fixation and stability of uncemented acetabular implant are influenced by peri-prosthetic bone ingrowth which is known to follow the principle of mechanoregulatory tissue differentiation algorithm. A tissue differentiation is a complex set of cellular events which are largely influenced by various mechanical stimuli. Over the last decade, a number of cell-phenotype specific algorithms have been developed in order to simulate these complex cellular events during bone ingrowth. Higher bone ingrowth results in better implant fixation. It is hypothesized that these cellular events might influence the peri-prosthetic bone ingrowth and thereby implant fixation. Using a three-dimensional (3D) microscale FE model representing an implant-bone interface and a cell-phenotype specific algorithm, the objective of the study is to evaluate the influences of various cellular activities on peri-prosthetic tissue differentiation. Consequently the study aims at identifying those cellular activities that may enhance implant fixation. The 3D microscale implant-bone interface model, comprising of Porocast Bead of BHR implant, granulation tissue and bone, was developed and meshed in ANSYS (Fig. 1b). Frictional contact (µ=0.5) was simulated at all interfaces. The displacement fields were transferred and prescribed at the top and bottom boundaries of the microscale model from a previously investigated macroscale implanted pelvis model (Fig. 1a) [4]. Periodic boundary conditions were imposed on the lateral surfaces. Linear elastic, isotropic material properties were assumed for all materials. Young's modulus and Poisson's ratios of bone and implant were mapped from the macroscale implanted pelvis [4]. A cell-phenotype specific mechanoregulatory algorithm was developed where various cellular activities and tissue formation were modeled with seven coupled differential equations [1, 2]. In order to evaluate the influence of various cellular activities, a Plackett-Burman DOE scheme was adopted. In the present study each of the cellular activity was assumed to be an independent factor. A total of 20 independent two-level factors were considered in this study which resulted in altogether 24 different combinations to be investigated. All these cellular activities were in turn assumed to be regulated by local mechanical stimulus [3]. The mechano-biological simulation was run until a convergence in tissue formation was attained. The cell-phenotype specific algorithm predicted a progressive transformation of granulation tissue into bone, cartilage and fibrous tissue (Fig. 1c). Various cellular activities were found to influence the time to reach equilibrium in tissue differentiation and, thereby, attainment of sufficient implant fixation (Fig. 2, Table 1). Negative regression coefficients were predicted for the significant factors, differentiation rate of MSCs and bone matrix formation rate, indicating that these cellular activities favor peri-prosthetic bone ingrowth by facilitating rapid peri-prosthetic bone ingrowth. Osteoblast differentiation rate, on the contrary, was found to have the highest positive regression coefficient among the other cellular activities, indicating that an increase in this cellular activity delays the attainment of equilibrium in bone ingrowth prohibiting rapid implant fixation. To view tables/figures, please contact authors directly

Total hip arthroplasty for developmental dysplasia of the hip (DDH) remains a difficult and challenging problem. How to reconstruct acetabular deficiencies has become increasingly important. One of the major causes inducing loosening of acetabular reinforcement ring with hook (Ganz ring) is insufficient initial stability. In this study, three-dimensional finite element models of the pelvis with different degrees of bone defect and acetabular components were developed to investigate the effects of the number of screws, screw insert position (Fig. 1), and bone graf quality on the initial stability under the peak load during normal walking. The size of pelvic bone defect, the number of screws and the position of screws were varied, according to clinical experience, to assess the change of initial stability of the Ganz ring. The Ganz ring was placed in the true acetabulum and the acetabular cup was cemented into the Ganz ring with 45 degrees abduction and 15 degrees of screws. The Insert position, nodes on the sacroiliac joint and the pubic symphysis were fixed in all degrees of freedom as the boundary condition. The peak load during normal walking condition was applied to the center of the femoral head (Fig. 2). According to the Crowe classification, as the degree of acetabular dysplasia was increased, the relative micromotion between the Ganz ring and pelvis was also increased. The peak micromotion increased as the stiffness of bone graft decreased. Increasing the numbers of screws, the relative micromotion tended to be reduced and varied the screw insertion position that affects the relative micromotion in the Ganz ring-pelvic interface (Fig. 3). This study showed that increasing the number of inserted screws can reduce the relative micromotion. Both the insert position and graft bone property affect the stability of the Ganz ring while the insert position has a greater impact. The current study is designed to lay the foundation for a biomechanical rationale that will support the choice of treatment

The use of two-dimensional plain X-rays for preoperative planning in total hip arthroplasty is unreliable. For example, in the presence of rotational hip contracture the lateral femoral off set can be significantly under-estimated. Pre-operative planning is of particular importance when using uncemented prostheses. The aim of this study was to determine the precision of a novel 3D CT-based preoperative planning methodology with the use of a cementless modular-neck femoral stem. Pre-operative computerised 3D planning was performed using HIP-PLAN® software for 223 patients undergoing THA with a cement-less cup and cement-less modular-neck stem. Components were chosen that best restored leg length and lateral off set. Postoperative anatomy was assessed by CT-scan and compared to the pre-operative plan. The implanted component was the same as the planned one in 86% of cases for the cup and 94% for the stem. There was no significant difference between the mean planned femoral anteversion (26.1° +/− 11.8) and the mean postoperative anteversion (26.9° +/− 14.1) (p=0.18), with good correlation between the two (coefficient 0.8). There was poor correlation, however, between the planned values and the actual post-operative values of acetabular cup anteversion (coefficient 0.17). The rotational centre of the hip was restored with a precision of 0.73mm +/3.5 horizontally and 1.2mm +/− 2 laterally. Limb length was restored with a precision of 0.3mm +/− 3.3 and femoral off set with a precision of 0.8mm +/− 3.1. There was no significant alteration in femoral off set (0.07mm, p=0.4) which was restored in 98% of cases. Almost all of the operative difficulties encountered were predicted pre-operatively. The precision of the three-dimensional pre-operative planning methodology investigated in this study is higher than that reported in the literature using two-dimensional X-ray templating. Cup navigation may be a useful adjunct to increase the accuracy of cup positioning

Introduction. Medial open wedge high tibial osteotomy (HTO) is a generally accepted surgical method for medial unicompartmental osteoarthritis with varus malalignment of the lower extremity. However, several authors have suggested the possibility of unintentional secondary changes during open wedge HTO, which include posterior tibial slope angle (PTS) change, tibial rotation change and medial–lateral slope change of the knee joint line, may influence knee kinematics and produce poor clinical outcomes. We sought to analyze postoperative changes in three-dimensional planes using a virtual wedge osteotomy 3D model. Pre- and post-operative changes in the medial proximal tibial angle (MPTA) in the coronal plane, posterior tibial slope (PTS) in the sagittal plane, and axial tibial rotation were measured as dependent variables. And this study was attempted to determine their mutual relationships and to clarify which independent variables, including hinge axis angle and gap ratio, affect tibial rotation change and PTS change by applying the identified hinge position. Method. A total of 17 patients with 19 knees underwent HTO and were evaluated with 3D-CT before and after surgery. A 3D model was constructed by applying reverse engineering software. Results. No significant linear correlation was observed between the three dependent variables: MPTA, PTS, and rotational change. Gap ratio (β = −0.2830, p = 0.0007) and hinge axis angle (β = 0.7395, p = 0.0005) were significant factors in determining rotation change with moderate correlation (R2 = 0.546 and 0.520, respectively). In univariate regression analysis, gap ratio (p = 0.6284) and hinge axis angle (p = 0.0968) were not significant factors determining the PTS; however, after controlling for confounder, rotation change, they became statistically significant (hinge axis: β = 0.44, p = 0.0059; gap ratio: β = 0.14, p = 0.0174). Discussion and Conclusion. Unchanged axial rotation is a requisite for constant unchanged PTS, and hinge axis angle have to be considered as an important independent variable for limitation of unintended secondary changes. This study might provide clues about the low reliability of intact slope angle, That is, representability of gap ratio as slope change can be interfered by rotational change, as a confounder. Also, the current study reported the external rotation tendency of proximal tibia with increasing hinge axis angle

Aims

In Asia and the Middle-East, people often flex their knees deeply in order to perform activities of daily living. The purpose of this study was to investigate the 3D kinematics of normal knees during high-flexion activities. Our hypothesis was that the femorotibial rotation, varus-valgus angle, translations, and kinematic pathway of normal knees during high-flexion activities, varied according to activity.

Purpose. As human soft tissue is anisotropic, non-linear and inhomogeneous, its properties are difficult to characterize. Different methods have been described that are either based on contact or noncontact protocols. In this study, three-dimensional (3D) digital image correlation (DIC) was adopted to examine the mechanical behaviour of the human Achilles tendon. Despite its wide use in engineering research and its great potential for strain and displacement measurements in biological tissue, the reported biomedical applications are rather limited. To our knowledge, no validation of 3D DIC measurement on human tendon tissue exists. The first goal of this study was to determine the feasibility to evaluate the mechanical properties of the human Achilles tendon under uniaxial loading conditions with 3D Digital Image Correlation. The second goal was to compare the accuracy and reproducibility of the 3D DIC against two linear variable differential transformer (LVDT's). Methods. Six human Achilles tendon specimens were prepared out of fresh frozen lower limbs. Prior to preparation, all limbs underwent CT-scanning. Using Mimics software, the volume of the tendons and the cross sectional area at each level could be calculated. Subsequently, the Achilles tendons were mounted in a custom made rig for uni-axial loading. Tendons were prepared for 3D DIC measurements with a modified technique that enhanced contrast and improved the optimal resolution. Progressive static loading up to 628,3 N en subsequent unloading was performed. Two charge-coupled device camera's recorded images of each loading position for subsequent strain analysis. Two LVDT's were mounted next to the clamped tendon in order to record the displacement of the grips. Results. 3D DIC strain measurement proved to be technical feasible on human tendon tissue if an adapted preparation protocol is used. A spatial resolution of 0,1 mm was reached. Accuracy analysis shows a very low scatter, comparable to that obtained in steel applications (0,03%). When compared to the LVDT measurements, DIC showed excellent correlation (R = 0.99). Apart from the longitudinal strain component, an important transverse strain component was revealed in all specimens (fig 1). Also a significant amount of slip was observed at the clamps. Through the non-contact nature of the measurement, this could be quantified and the analysis became independent of any slip (fig 2). The strain distribution was of a strongly inhomogeneous nature, both within the same specimen (fig 1) and amongst different specimens. Conclusion. 3D DIC is a very promising technique for strain measurement of human collagenous tissue. Accuracy analyses indicate a very low scatter, comparable to that obtained in traditional steel applications. The major advantages of the DIC technique over the LVDTs is the 3D, non-contact, full-field nature of the analysis and the possibility to analyse multidirectional strain, without disturbing slip effects in the grips

Osteoarthritis results in changes in the dimensions of the glenoid. This study aimed to assess the size and radius of curvature of arthritic glenoids. A total of 145 CT scans were analysed, performed as part of routine pre-operative assessment before total shoulder replacement in 91 women and 54 men. Only patients with primary osteoarthritis and a concentric glenoid were included in the study. The CT scans underwent three-dimensional (3D) reconstruction and were analysed using dedicated computer software. The measurements consisted of maximum superoinferior height, anteroposterior width and a best-fit sphere radius of curvature of the glenoid.

The mean height was 40.2 mm (sd 4.9), the mean width was 29 mm (sd 4.3) and the mean radius of curvature was 35.4 mm (sd 7.8). The measurements were statistically different in men and women and had a Gaussian distribution with marked variation. All measurements were greater than the known values in normal subjects.

With current shoulder replacement systems using a unique backside radius of curvature for the glenoid component, there is a risk of undertaking excessive reaming to adapt the bone to the component resulting in sacrifice of subchondral bone or under-reaming and instability of the component due to a ’rocking horse‘ phenomenon.

Cite this article: Bone Joint J 2013;95-B:1377–82.

The aim of this study was to investigate upper limb botulinum toxin A (BTX-A) injections in children with spastic hemiplegia. Ten children with hemiplegia, aged 10–17 years, received upper limb BTX-A injections and 6 weeks therapy. BTX-A was injected using EMG guidance into elbow and wrist flexors, and forearm pronators (dose 1–2 units/kg body wt (Botox®) per muscle). Follow-up assessments continued to 24 weeks post BTX-A. Outcome measures included three-dimensional (3-D) upper limb analysis of functional tasks, Melbourne Assessment; passive range of motion (PROM), and muscle tone. There were no serious adverse effects. Elbow flexor muscle tone was reduced to 12 weeks post BTX-A (p < 0.05). Mean passive elbow supination increased by 19 degrees (not significant, p= 0.3). Pre-injection 3-D analysis showed that, compared to controls, children with hemiplegia were slower at performing upper limb reaching tasks, using less elbow extension and supination, and utilising increased compensatory trunk forward flexion. Post BTX-A, the time to complete upper limb tasks did not change (p> 0.15). However, at least six subjects had increased elbow extension (average 17 degrees) and decreased trunk forward flexion (average 16 degrees) during upper limb reaching tasks. Five subjects improved their Melbourne Assessment score by 5% or greater. Decreased tone and individual improvements in upper limb functional tasks were seen post BTX-A and therapy. However deficits in timing of upper limb movements did not change post BTX-A

Aims

Patient-specific glenoid guides (PSGs) claim an improvement in accuracy and reproducibility of the positioning of components in total shoulder arthroplasty (TSA). The results have not yet been confirmed in a prospective clinical trial. Our aim was to assess whether the use of PSGs in patients with osteoarthritis of the shoulder would allow accurate and reliable implantation of the glenoid component.

Bone marrow-derived mesenchymal stromal stem cells (BMSCs) are a promising cell source for treating articular cartilage defects. Quality of cartilaginous repair tissue following BMSC transplantation has been shown to correlate with functional outcome. Therefore, tissue-engineering variables, such as cell expansion environment and seeding density of scaffolds, are currently under investigation. The objectives of this study were to demonstrate chondrogenic differentiation of BMSCs seeded within a collagen I scaffold following isolation and expansion in two-dimensional (2D) and three-dimensional (3D) environments, and assess the impact of seeding density on in vitro chondrogenesis. It was hypothesised that both expansion protocols would produce BMSCs capable of hyaline-like chondrogenesis with an optimal seeding density of 10 million cells/cm3. Ovine BMSCs were isolated in a 2D environment by plastic adherence, expanded to passage two in flasks containing expansion medium, and seeded within collagen I scaffolds (6 mm diameter, 3.5 mm thickness and 0.115 ± 0.020 mm pore size; Integra LifeSciences Corp.) at densities of 50, 10, 5, 1, and 0.5 million BMSCs/cm3. For 3D isolation and expansion, bone marrow aspirates containing known quantities of mononucleated cells (BMNCs) were seeded on scaffolds at 50, 10, 5, 1, and 0.5 million BMNCs/cm3 and cultured in expansion medium for an equivalent duration to 2D expansion. All cell-scaffold constructs were differentiated in vitro in chondrogenic medium containing transforming growth factor-beta three for 21 days and assessed with RT-qPCR, safranin O staining, histological scoring using the Bern Score, collagen immunofluorescence, and glycosaminoglycan (GAG) quantification. Two dimensional-expanded BMSCs seeded at all densities were capable of proteoglycan production and displayed increased expressions of aggrecan and collagen II mRNA relative to pre-differentiation controls. Collagen II deposition was apparent in scaffolds seeded at 0.5–10 million BMSCs/cm3. Chondrogenesis of 2D-expanded BMSCs was most pronounced in scaffolds seeded at 5–10 million BMSCs/cm3 based on aggrecan and collagen II mRNA, safranin O staining, Bern Score, total GAG, and GAG/DNA. For 3D-expanded BMSC-seeded scaffolds, increased aggrecan and collagen II mRNA expressions relative to controls were noted with all densities. Proteoglycan deposition was present in scaffolds seeded at 0.5–50 million BMNCs/cm3, while collagen II deposition occurred in scaffolds seeded at 10–50 million BMNCs/cm3. The highest levels of aggrecan and collagen II mRNA, Bern Score, total GAG, and GAG/DNA occurred with seeding at 50 million BMNCs/cm3. Within a collagen I scaffold, 2D- and 3D-expanded BMSCs are capable of hyaline-like chondrogenesis with optimal cell seeding densities of 5–10 million BMSCs/cm3 and 50 million BMNCs/cm3, respectively. Accordingly, these densities could be considered when seeding collagen I scaffolds in BMSC transplantation protocols

Introduction: The cement mantle is a critical factor in the longevity of cemented total hip arthroplasty (THA). Concern has been raised about the reliability of plain radiographs for its assessment. A new high-definition, three-dimensional (3-D), in vitro method of cement mantle evaluation has been developed. Aim: To compare cement mantle quality in six contemporary stem designs. Methods: Exact resin replicas of six contemporary stem designs were implanted into cadaver femora using third generation techniques. The specimens were imaged with a high-speed, helical, computerised, tomographic scanner. Computer-assisted, 3-D analysis of the cement mantle thickness was made. Comparisons were made between different stem designs and also with plain film assessments of the mantles. Results: Standard radiographs overestimated mantle thickness (p< 0.05) and underestimated the deficiencies. The percentage area of cement mantle that was thinner than 2mm ranged from 9% to 28%. Slight malrotation or malalignment of the stem with respect to the broach envelope produced deficient mantles. Characteristic patterns of deficiencies were seen for different stem designs. Conclusions: Plain x-rays overestimated the cement thickness, frequently missed areas of substandard cement, and should, therefore, be interpreted cautiously. The cement mantle varies widely depending on the stem design and surgical technique, and commonly used designs have significant deficiencies in their mantles by standard criteria despite proper surgical technique. Surgeons should be familiar with the stem that they use and its instrumentation to maximise outcomes. This is a valuable technique for the study of the cement mantle as it relates to implant design, surgical technique and patient anatomy

Introduction: Appropriate femoral component alignment is important for long-term survival of total knee arthroplasty (TKA). Valgus angle of femoral component is recommended as the angle between mechanical axis and anatomical axis of the femur. Intramedullary guide system is widely used for determining the valgus positioning of femoral component. Entry point of intramedullary guide is one of the key factors for determining valgus angle of femoral component. Some investigators have shown appropriate entry points of intramedullary guide, however, it is still unclear. In this study, appropriate entry point of intramedullary guide system was calculated using three-dimensional digital templating software “Athena” (Soft Cube, Osaka, Japan). Method: Forty-one knees in 34 osteoarthritis patients except valgus deformity (30 females and 4 males, mean age 75.1 years) received TKA and were simulated using “Athena” from January 2009 to March 2009. All cases were grade III or IV in Kellgren-Lawrence index. Radiograph and CT scan image were used for determination of appropriate entry point of femur using “Athena”. The anatomical axis of femur was defined as a line connecting the midpoints of femoral AP and lateral diameter, at 60 mm and 110 mm proximal to the center of intercondylar notch. Two coordinate systems were configured as representation of entry points. One was at the center of intercondylar notch defined as the point of origin in axial view of CT image and the line parallel to the clinical epicondylar axis (cTEA) defined as X-axis. Another coordinate system was the same point of origin but parallel to the line between trochlear groove and the center of intercondylar notch (AP line) defined as Y-axis. Result: In the coordinate system that defined the cTEA as the X-axis, the average of entry point was 0.3± 0.30 mm medial (range, −4.8~ 4.7mm) and 11.6 ± 0.52mm anterior (range, 3.1~ 16.5mm) to the center of intecondylar notch. In the other coordinate system that defined AP line as the Y-axis, the average of entry point was 2.6± 0.29 mm medial (range, −1.5~ 6.3mm) and 11.2±0.52 mm anterior (range, 2.8~ 16.0mm) to the center of intercondylar notch. Discussion: In this study, the appropriate entry point of intramdullary guide was slightly medial and about 11mm anterior to the center of intercondylar notch on average. However, individual entry point varied considerably in distance. These data indicates that it is important to simulate the appropriate entry point of intramedullary guide in preoperative planning

Purpose: To evaluate femoral head coverage with three-dimensional computed tomographic (3D CT) reconstruction after Pemberton’s pericapsular osteotomy with open reduction in cases with developmental dysplasia of the hip (DDH). In a prospective study, routine anteroposterior (AP) radiographs and 3D CT reconstruction of the pelvis in 15 consecutive patients with DDH were obtained pre-operatively and six months after surgery. In all patients, a Pemberton’s pericapsular osteotomy with open reduction was performed. The mean age of the patients at the time of surgery was 26 months (range 18 to 34) and 32 months (range 24 to 40) months at the last follow-up. Twelve of the patients were girls and three were boys. The 3D images were studied by using the anterior, posterior, lateral, and inferior views to analyse changes in the acetabular position in the frontal, sagittal, and trns-verse planes. Acetabular indices on radiographs and anterolateral acetabular lip angle (ALAL) on anterior view, posterolateral acetabular lip angle (PLAL) on posterior view, lateral acetabular inclination (LAI) on lateral view, and transverse rotation of the acetabulum (TR) on inferior view were measured pre- and postoperatively. Furthermore, coverage of the femoral head was classified according to Azuma’s criteria on anterior and posterior views. The mean acetabular index was 38 degrees (range 33 to 52) preoperatively and 19 degrees (range 16 to 23) postoperatively. Comparison between pre- and postoperative 3D CT reconstruction images revealed increased acetabular adduction and extension, and decreased ace-tabular anteversion in all cases. Sufficient coverage of the femoral head was documented in all patients. Pre- and postoperative mean measurements on 3D CT reconstruction images are as follows: ALAL, 33 (range 29-40) – 16 (range 14-20); PLAL, 49 (range 46-52) – 29 (range 26-31); LAI, 48 (range 40-64) – 27 (range 25-30); TR, 13 (range 9-15) – 6 (range 5-10). Coverage of the femoral head was grade I in all patients according to Azuma’s criteria. Conclusions: Pemberton’s pericapsular osteotomy provides successful results in appropriate cases, with sufficient coverage of the femoral head. However, if there is any doubt, utilisation of 3D CT reconstruction images may contribute to a more precise evaluation of the outcome

Using radiography and computer tomography (CT) we studied the morphology of 83 hips in 69 Caucasian adults with osteoarthritis secondary to developmental dysplasia of the hip (DDH). A previously published series of 310 hips with primary osteoarthritis was used as a control group. According to the Crowe classification, 33 of the dysplastic hips were graded as class I, 27 as class II and 23 as class III or class IV.

The intramedullary femoral canal had reduced mediolateral and anteroposterior dimensions in all groups compared with the control group. Only in Crowe class II hips was the femoral neck-shaft angle increased. The proximal femur had more anteversion in all the developmental dysplasia of the hip groups, ranging from 2° to 80°. Templated measurement of acetabular dimensions for plain radiography closely matched measurements taken by CT.

The results of our study confirm the observations previously confined to the Japanese population.

Background

Massive rotator cuff tears and consequent cuff-deficient arthritis (CTA) of the shoulder can cause severe shoulder dysfunction in the elderly. Reverse total shoulder arthroplasty (RTSA) has been widely used for treatment of CTA in all over the world since its introduction in the 90's. In Japan, however, we have just started to clinically use RTSA from April 2014. In addition, we have only one choice of the implants (Aequalis Reverse, Tornier) currently, and only one size of the base-plate of the glenoid component (29 mm in diameter) is available so far. Japanese, especially elderly people, have generally smaller figure than Caucasians. We are not sure whether the base-plate would fit for the smaller Japanese. The purpose of this study was to measure the size of the glenoids in Japanese using CT images and to examine that they would fit the 29 mm base-plate.

Restoration of joint line in total knee arthroplasty (TKA) is important for kinematics of knee and ligamentous balance. Especially in revision TKA, it may be difficult to identify the joint line. The aim of this study is to define the relationship between epicondyles and articular surface using CT based three-dimensional digital templating sofware $“Athena” (Soft Cube, Osaka, Japan). 137 knees with osteoarthritis, all caces were grade 2 or lower in Kellgren-Lawrence index, were investigated. Perpendicular lines were dropped from the prominences of the medial and lateral femoral epicondyles to the most distal points of articular surfaces and distances of the lines were measured on the axial and coronal planes. The femoral width was measured as the distance between medial and lateral epicondyles. Each of the distance described above was converted to a ratio by dividing by the femoral width. On the axial plane, the average distance from epicondyles to the posterior articular surfaces were 29.4±2.2mm on the medial side and 21.2±2.3mm on the lateral side. The average of the femoral width was 75.2±4.1mm. On coronal plane, the average distance from epicondyles to the distal articular surfaces were 25.2±2.8mm on the medial side and 21.4±2.5mm on the lateral side. The ratio for the distance from epicondyles to the distal and posterior joint line compared to femoral width was 0.39±0.02, 0.28±0.03, 0.33±0.03 and 0.28±0.03. The distance from epicondyles to the distal and posterior joint line correlates with the femoral width of the distal femur. This information can be useful in determining appropriate joint line

Introduction

The deformity in osteoarthritis (OA) of the knee has been evaluated mainly in the frontal plane two dimensional X-ray using femorotibial angle. Although the presence of underlying rotational deformity in the varus knee and coexisting hip abnormality in the valgus knee have been suggested, three dimensional (3D) deformities in the varus and valgus knee were still unknown. We evaluated the 3D deformities of the varus and valgus knee using 3D bone models.

Background

The use of Computed Tomography (CT) as a medical imaging tool has widespread applications in the field of knee surgery. Surgeons use a CT scan in a conventional way during the pre-operative stage, to plan the position of the femoral component in the horizontal plane. In the post-operative stage, the use of a CT scan is a routine tool in the evaluation of failed TKA as rotational malalignment of the femoral component has been determined as a cause of poor clinical outcome after TKA.

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.

Introduction

Osteoarthritis continues to be a major cause of pain and disability. The pathological processes leading to the end-stage of joint degeneration remain poorly understood. Advances in radiological imaging have the potential to improve understanding of the structural and functional changes observed in OA. The aim of this study was to describe the microarchitecture of the femoral head in osteoarthritis.

Introduction

The equine SDFT tendon is a complex hierarchal structure that transmits force from muscle to bone and stores energy through its stretching and recoiling action. It is a common site of pathology in athletic horses. Our aim was to describe the ultrastructural anatomy of the SDFT as part of a larger programme to understand the structure-functional relationship of this tendon.

Introduction

The Flexible Nichidai Knee (FNK) System (Nakashima Medical, Japan) was designed to fit Asian knees. Especially, the posterior stabilized(PS) prosthesis was designed as semi-constrained posterior stabilized system that had a large tibial post and femoral articulation. We hypothesized that the semi-constrained PS implant design would have a positive influence on vivo kinematics after total knee arthroplasty (TKA).