Background/Purpose. Cross-linked polyethylene (XLPE) has shown reduced wear rates as compared to conventional polyethylene, but the long-term effect of this on the incidence of osteolysis remains unclear. In addition, the measurement of osteolysis on plain radiographs can underestimate the incidence and extent of osteolysis. Therefore, we evaluated the wear rate, incidence and volume of osteolysis at a minimum follow-up of ten years using three-dimensional computed tomography (3-D CT), a more accurate and sensitive method for detecting and measuring the size of osteolysis than plain radiographs. Materials and Methods. Between 2000 and 2004, 233 primary THAs were performed using 28-mm cobalt-chrome femoral head on first-generation XLPE (Longevity. ®. , Zimmer, Warsaw, IN) with cups of identical design. Fifty-five patients (57 hips) deceased, eight patients (8 hips) were lost and four patients (4 hips) were revised due to recurrent dislocation (2 hips) or infection (2 hips). Among the remaining 164 hips, 95 hips underwent 3-D CT scanning (Aquilion® 64, Lightspeed Ultra® 16 or Optima® 660) at minimum 10 years (range, 10.0 to 15.2) and were included in this study. Mean age at the time of THA was 56.2 years and average body mass index was 23.5 kg/m. 2. Average cup size was 55.4 mm whereas mean inclination and anteversion angle of cups on CT scan were 40.1 and 17.4 degrees, respectively. Average follow-up period was 12.8 years. 2D wear rate was measured using PolyWare® 3D Rev 7 software (Draftware Inc, Vevay, IN). Osteolysis was strictly defined as a localized area of trabecular loss with a sclerotic margin. Osteoarthritic cyst and age-related osteoporosis were excluded using perioperative CT scan and magnetic resonance imaging or serial plain radiographs. The incidence, location, and volume of osteolysis were measured. Results. Mean bedding-in wear rate (<1 yr) was 0.085 mm and average annual wear rate was 0.023 ± 0.012 mm/yr. Seven hips (7.4%) demonstrated osteolysis on 3-D CT scan: Acetabular osteolysis was measured with an average volume of 3.2 cm. 3. in zone 1 or 2 in three hips whereas femoral osteolysis was demonstrated with a mean volume of 0.7 cm. 3. in zone 1 or 7 in 5 hips. One hip showed both acetabular and femoral osteolysis. Conclusion. The results of THA using first-generation XLPE were encouraging with low wear rate as well as low incidence of osteolysis at a minimum follow-up of ten years. Longer follow-up is necessary to determine if this XLPE will continue to demonstrate the improved osteolysis characteristics. Acknowledgement: This work was supported by Institute for Information & communications Technology Promotion (IITP) grant funded by the Korea government (MSIP) (#B0101-14-1081)

Three-dimensional CT was used to examine the atlantoaxial joint of a nine-year-old girl who presented with fixed rotation of the head 3.5 months after an apparently spontaneous acute torticollis. The method provided clear, anatomical images to show the site, extent and direction of the type-I rotatory fixation (Fielding and Hawkins 1977). The 3-D reconstructions helped to guide manipulation which was successful in this late case.

We evaluated (1) wear rate, (2) prevalence and volume of osteolysis using 3D-CT scan, (3) other bearing-related complications, (4) HHS and survivorship free from revision at 15 years after THA using first-generation XLPE (1G XLPE).

One-hundred sixty THAs were evaluated regarding bearing-related complication, HHS and survivorship. Among them, 112 hips underwent 3D-CT to analyze wear rate and osteolysis. All THAs were performed by single surgeon using cup of identical design, a 28-mm metal head and 1G XLPE (10 Mrad). Average age were 57 years and mean follow-up was 15.2 years. 3D-CT scan was performed at average of 13.0 years. Clinical evaluation included HHS and radiographic analysis was performed regarding stem alignment, cup anteversion and inclination angle, component stability, wear rate and osteolysis. Wear was measured using digital software. The prevalence and volume of osteolysis were also evaluated. Complications included XLPE dissociation/rim fracture, dislocation, periprosthetic fracture, infection, HO and any revision. Survivorship free from revision at 15 years was estimated.

Average inclination and anteversion angle of cups were 40.7° and 20.6°. Mean stem alignment was 0.1° valgus. Average bedding-in and annual wear rate wear rate was 0.085 mm and 0.025 mm/yr. Eleven hips (10%) demonstrated osteolysis; pelvic osteolysis with average volume of 1.4 cm³ in six and femoral osteolysis with mean size of 0.4 cm² in seven hips. Of 160 THAs, 5 hips (3%) dislocated. Overall, bearing-related complications occurred in 16 hips (10%). Other complications included postoperative periprosthetic fracture in 4 (3%), infection and HO in 3 hips, respectively. No hip demonstrated loosening, XLPE rim fracture/dissociation. Seven THAs (4%) were revised; recurrent dislocation in 5 and periprosthetic joint infection in 2 hips. Average HHS at last follow-up improved from 47.7 preoperatively to 91.2 points (p<0.001). Estimated survivorship free from revision at 15 years was 95.6 %.

THA using 1G XLPE demonstrated low wear rate as well as low incidence of osteolysis at average follow-up of fifteen years. Longer-term studies will be necessary to determine if XLPE will continue to demonstrate this improved osteolysis characteristics.

Aims

Posterior column plating through the single anterior approach reduces the morbidity in acetabular fractures that require stabilization of both the columns. The aim of this study is to assess the effectiveness of posterior column plating through the anterior intrapelvic approach (AIP) in the management of acetabular fractures.

Tightrope fixation is known method for reconstructing acromioclavicular joint and the presence of good bone stock around the two drillholes is the most important determining factor for preventing failure.

Aims

Low-energy distal radius fractures (DRFs) are the most common upper arm fractures correlated with bone fragility. Vitamin D deficiency is an important risk factor associated with DRFs. However, the relationship between DRF severity and vitamin D deficiency is not elucidated. Therefore, this study aimed to identify the correlation between DRF severity and serum 25-hydroxyvitamin-D level, which is an indicator of vitamin D deficiency.

Aims

The aim of this study was to describe a quantitative 3D CT method to measure rotator cuff muscle volume, atrophy, and balance in healthy controls and in three pathological shoulder cohorts.

Glenoid baseplate orientation in reverse shoulder arthroplasty (RSA) influences clinical outcomes, complications, and failure rates. Novel technologies have been produced to decrease performance heterogeneity of low and high-volume surgeons. This study aimed to determine novice and experienced shoulder surgeon's ability to accurately characterise glenoid component orientation in an intra-operative scenario. Glenoid baseplates were implanted in eight fresh frozen cadavers by novice surgical trainees. Glenoid baseplate version, inclination, augment rotation, and superior-inferior centre of rotation (COR) offset were then measured using in-person visual assessments by novice and experienced shoulder surgeons immediately after implantation. Glenoid orientation parameters were then measured using 3D CT scans with digitally reconstructed radiographs (DRRs) by two independent observers. Bland-Altman plots were produced to determine the accuracy of glenoid orientation using standard intraoperative assessment compared to postoperative 3D CT scan results. Visual assessment of glenoid baseplate orientation showed “poor” to “fair” correlation to 3D CT DRR measurements for both novice and experienced surgeon groups for all measured parameters. There was a clinically relevant, large discrepancy between intra-operative visual assessments and 3D CT DRR measurements for all parameters. Errors in visual assessment of up to 19.2 degrees of inclination and 8mm supero-inferior COR offset occurred. Experienced surgeons had greater measurement error than novices for all measured parameters. Intra-operative measurement errors in glenoid placement may reach unacceptable clinical limits. Kinesthetic input during implantation likely improves orientation understanding and has implications for hands-on learning

Aims. This study aims to describe a new method that may be used as a supplement to evaluate humeral rotational alignment during intramedullary nail (IMN) insertion using the profile of the perpendicular peak of the greater tuberosity and its relation to the transepicondylar axis. We called this angle the greater tuberosity version angle (GTVA). Methods. This study analyzed 506 cadaveric humeri of adult patients. All humeri were CT scanned using 0.625 × 0.625 × 0.625 mm cubic voxels. The images acquired were used to generate 3D surface models of the humerus. Next, 3D landmarks were automatically calculated on each 3D bone using custom-written C++ software. The anatomical landmarks analyzed were the transepicondylar axis, the humerus anatomical axis, and the peak of the perpendicular axis of the greater tuberosity. Lastly, the angle between the transepicondylar axis and the greater tuberosity axis was calculated and defined as the GTVA. Results. The value of GTVA was 20.9° (SD 4.7°) (95% CI 20.47° to 21.3°). Results of analysis of variance revealed that females had a statistically significant larger angle of 21.95° (SD 4.49°) compared to males, which were found to be 20.49° (SD 4.8°) (p = 0.001). Conclusion. This study identified a consistent relationship between palpable anatomical landmarks, enhancing IMN accuracy by utilizing 3D CT scans and replicating a 20.9° angle from the greater tuberosity to the transepicondylar axis. Using this angle as a secondary reference may help mitigate the complications associated with malrotation of the humerus following IMN. However, future trials are needed for clinical validation. Cite this article: Bone Jt Open 2024;5(10):929–936

Aims. The purpose of this study was to develop a convolutional neural network (CNN) for fracture detection, classification, and identification of greater tuberosity displacement ≥ 1 cm, neck-shaft angle (NSA) ≤ 100°, shaft translation, and articular fracture involvement, on plain radiographs. Methods. The CNN was trained and tested on radiographs sourced from 11 hospitals in Australia and externally validated on radiographs from the Netherlands. Each radiograph was paired with corresponding CT scans to serve as the reference standard based on dual independent evaluation by trained researchers and attending orthopaedic surgeons. Presence of a fracture, classification (non- to minimally displaced; two-part, multipart, and glenohumeral dislocation), and four characteristics were determined on 2D and 3D CT scans and subsequently allocated to each series of radiographs. Fracture characteristics included greater tuberosity displacement ≥ 1 cm, NSA ≤ 100°, shaft translation (0% to < 75%, 75% to 95%, > 95%), and the extent of articular involvement (0% to < 15%, 15% to 35%, or > 35%). Results. For detection and classification, the algorithm was trained on 1,709 radiographs (n = 803), tested on 567 radiographs (n = 244), and subsequently externally validated on 535 radiographs (n = 227). For characterization, healthy shoulders and glenohumeral dislocation were excluded. The overall accuracy for fracture detection was 94% (area under the receiver operating characteristic curve (AUC) = 0.98) and for classification 78% (AUC 0.68 to 0.93). Accuracy to detect greater tuberosity fracture displacement ≥ 1 cm was 35.0% (AUC 0.57). The CNN did not recognize NSAs ≤ 100° (AUC 0.42), nor fractures with ≥ 75% shaft translation (AUC 0.51 to 0.53), or with ≥ 15% articular involvement (AUC 0.48 to 0.49). For all objectives, the model’s performance on the external dataset showed similar accuracy levels. Conclusion. CNNs proficiently rule out proximal humerus fractures on plain radiographs. Despite rigorous training methodology based on CT imaging with multi-rater consensus to serve as the reference standard, artificial intelligence-driven classification is insufficient for clinical implementation. The CNN exhibited poor diagnostic ability to detect greater tuberosity displacement ≥ 1 cm and failed to identify NSAs ≤ 100°, shaft translations, or articular fractures. Cite this article: Bone Joint J 2024;106-B(11):1348–1360

Abstract. Introduction. Recurrent groin pain following periacetabular osteotomy (PAO) is a challenging problem. The purpose of our study was to evaluate the position and dynamics of the psoas tendon as a potential cause for recurrent groin pain following PAO. Methods. Patients with recurrent groin pain following PAO were identified from a single surgeon series. A total of 13 patients with 18 hips (4.7%) out of a 386 PAO, had recurrent groin pain. Muscle path of the psoas tendon was accurately represented using 3D models from CT data were created with Mimics software. A validated discrete element model using rigid body springs was used to predict psoas tendon movement during hip circumduction and walking. Results. Five out of the 18 hips did not show any malformations at the osteotomy site. Thirteen hips (72%) showed malformation secondary to callus at the superior pubic ramus. These were classified into: osteophytes at the osteotomy site, hypertrophic callus or non-union and malunion at the osteotomy. Mean minimal distance of the psoas tendon to osteophytes was found to be 6.24 mm (n=6) and to the osteotomy site was 14.18 mm (n=18). Conclusions. Recurrent groin pain after PAO needs a thorough assessment. One need to have a high suspicion of psoas issues as a cause. 3D CT scan may be necessary to identify causes related to healing of the pubic osteotomy. Dynamic ultrasound of the psoas psoas tendon may help in evaluating for psoas impingement as a cause of recurrent groin pain in these cases

Aims. A fracture of the medial tibial plateau is a serious complication of Oxford mobile-bearing unicompartmental knee arthroplasty (OUKA). The risk of these fractures is reportedly lower when using components with a longer keel-cortex distance (KCDs). The aim of this study was to examine how slight varus placement of the tibial component might affect the KCDs, and the rate of tibial plateau fracture, in a clinical setting. Methods. This retrospective study included 255 patients who underwent 305 OUKAs with cementless tibial components. There were 52 males and 203 females. Their mean age was 73.1 years (47 to 91), and the mean follow-up was 1.9 years (1.0 to 2.0). In 217 knees in 187 patients in the conventional group, tibial cuts were made orthogonally to the tibial axis. The varus group included 88 knees in 68 patients, and tibial cuts were made slightly varus using a new osteotomy guide. Anterior and posterior KCDs and the origins of fracture lines were assessed using 3D CT scans one week postoperatively. The KCDs and rate of fracture were compared between the two groups. Results. Medial tibial fractures occurred after surgery in 15 patients (15 OUKAs) in the conventional group, but only one patient (one OUKA) had a tibial fracture after surgery in the varus group. This difference was significant (6.9% vs 1.1%; p = 0.029). The mean posterior KCD was significantly shorter in the conventional group (5.0 mm (SD 1.7)) than in the varus group (6.1 mm (SD 2.1); p = 0.002). Conclusion. In OUKA, the distance between the keel and posterior tibial cortex was longer in our patients with slight varus alignment of the tibial component, which seems to decrease the risk of postoperative tibial fracture. Cite this article: Bone Joint J 2022;104-B(10):1118–1125

Aims. This study aimed to answer the following questions: do 3D-printed models lead to a more accurate recognition of the pattern of complex fractures of the elbow?; do 3D-printed models lead to a more reliable recognition of the pattern of these injuries?; and do junior surgeons benefit more from 3D-printed models than senior surgeons?. Methods. A total of 15 orthopaedic trauma surgeons (seven juniors, eight seniors) evaluated 20 complex elbow fractures for their overall pattern (i.e. varus posterior medial rotational injury, terrible triad injury, radial head fracture with posterolateral dislocation, anterior (trans-)olecranon fracture-dislocation, posterior (trans-)olecranon fracture-dislocation) and their specific characteristics. First, fractures were assessed based on radiographs and 2D and 3D CT scans; and in a subsequent round, one month later, with additional 3D-printed models. Diagnostic accuracy (acc) and inter-surgeon reliability (κ) were determined for each assessment. Results. Accuracy significantly improved with 3D-printed models for the whole group on pattern recognition (acc. 2D/3D. = 0.62 vs acc. 3Dprint. = 0.69; Δacc = 0.07 (95% confidence interval (CI) 0.00 to 0.14); p = 0.025). A significant improvement was also seen in reliability for pattern recognition with the additional 3D-printed models (κ. 2D/3D. = 0.41 (moderate) vs κ. 3Dprint. = 0.59 (moderate); Δκ = 0.18 (95% CI 0.14 to 0.22); p ≤ 0.001). Accuracy was comparable between junior and senior surgeons with the 3D-printed model (acc. junior. = 0.70 vs acc. senior. = 0.68; Δacc = -0.02 (95% CI -0.17 to 0.13); p = 0.904). Reliability was also comparable between junior and senior surgeons without the 3D-printed model (κ. junior. = 0.39 (fair) vs κ. senior. = 0.43 (moderate); Δκ = 0.03 (95% CI -0.03 to 0.10); p = 0.318). However, junior surgeons showed greater improvement regarding reliability than seniors with 3D-printed models (κ. junior. = 0.65 (substantial) vs κ. senior. = 0.54 (moderate); Δκ = 0.11 (95% CI 0.04 to 0.18); p = 0.002). Conclusion. The use of 3D-printed models significantly improved the accuracy and reliability of recognizing the pattern of complex fractures of the elbow. However, the current long printing time and non-reusable materials could limit the usefulness of 3D-printed models in clinical practice. They could be suitable as a reusable tool for teaching residents. Cite this article: Bone Joint J 2023;105-B(1):56–63

Introduction: Reversed prostheses implantation requires screwing of the glenoid component with prefixed angles. This study is to determine anatomical angles of scapula that take part in reversed prostheses implantation. Material and method: Seventy-three 3-dimensional computed tomography of the scapula and 108 scapular dry specimens were analyzed. Mean age of the CT-3D serie was of 52.59 years old (ranging from 16 to 84). There were 46 females and 27 males. The following measures were made on each patient: length of the neck of the inferior glenoid, angle between the glenoid surface and the upper posterior column of the scapula, angle between the major craneo-caudal glenoid axis and the base of the coracoid process and angle between the major craneo-caudal glenoid axis and the upper posterior column of the scapula. Measures were performed in the AP view as well as in the posterior view of the scapula. Results: The length of the neck of the anterior glenoid was classified into two groups named ‘short-neck’ and ‘long-neck’ for both three-dimensional computed tomography and cadaveric scapulas with statistically significant differences between both groups (p< 0,001 for the three-dimensional computed tomography scapulas and p=0,034 for the cadaveric group). The angle between the glenoid surface and the upper posterior column of the scapula was also classified into two different types: type I (52° ranging from 48° to 57°) and type II (64° ranging from 60° to 70°) with statistically significant differences between both groups (p< 0,001 for the three-dimensional computed tomography scapulas and p< 0,001 for the cadaveric group). The angle between the major craneo-caudal glenoid axis and the center of the base of the coracoid process averaged 18,25° (ranging 13° from to 27°). The angle between the major craneo-caudal glenoid axis and the upper posterior column of the scapula averaged 8° (ranging 5° from to 18°). Conclusions:. - scapulas can be classified into two groups regarding the angle between the glenoid surface and the upper posterior column of the scapula with significant differences between them. - two different lengths of the neck of the inferior glenoid body have also been differentiated in the anterior as well as in the posterior faces of the scapula. - the base of the coracoid process is not in line with the posterior column of the scapula. - three-dimensional computed tomography of the scapula constitutes and important tool when planning reversed prostheses implantation

Background: Complex fractures of the tibial plateau can be difficult to characterize on plain radiographs and two-dimensional computed tomography scans. We tested the hypothesis that three-dimensional computed tomography reconstructions improve the reliability of tibial plateau fracture characterization and classification. Methods: Forty-five consecutive intra-articular fractures of the tibial plateau were evaluated by six independent observers for the presence of six fracture characteristics that are not specifically included in currently used classification schemes:. posteromedial shear fracture;. coronal plane fracture;. lateral condylar impaction;. medial condylar impaction;. tibial spine involvement;. separation of tibial tubercle necessitating anteroposterior lag screw fixation. In addition, fractures were classified according to the AO/OTA Comprehensive Classification of Fractures, the Schatzker classification system and the Hohl and Moore system. Two rounds of evaluation were performed and then compared. First, a combination of plain radiographs and two-dimensional computed tomography scans (2D) were evaluated, and then, four weeks later, a combination of radiographs, two-dimensional computed tomography scans, and three-dimensional reconstructions of computed tomography scans (3D) were assessed. Results: Interobserver agreement improved for all classification systems after the addition of three-dimensional reconstructions (AO/OTA κ2D = 0.536 versus κ3D = 0.545; Schatzker κ2D = 0.545 versus κ3D = 0.596; Hohl and Moore κ2D = 0.668 versus κ3D = 0.746). Three-dimensional computed tomography reconstructions also improved the average intraobserver reliability for all fracture characteristics, from κ2D = 0.624 (substantial agreement) to κ3D = 0.687 (substantial agreement). The addition of three-dimensional images had limited infiuence on the average interobserver reliability for the recognition of specific fracture characteristics (κ2D = 0.488 versus κ3D = 0.485, both moderate agreement). Three-dimensional computed tomography images improved interobserver reliability for the recognition of coronal plane fractures from fair (κ2D = 0.398) to moderate (κ3D = 0.418) but this difference was not statistically significant. Conclusions: Three-dimensional computed tomography is helpful for;. individual orthopaedic surgeons for preoperative planning (improves intraobserver reliability for the recognition of fracture characteristics), and for. comparison of clinical outcomes in the orthopaedic literature (improves interobserver reliability of classification systems)

Purpose. Patients with acetabular dysplasia demonstrate altered biomechanics during gate and other activities. We hypothesized that these patients exhibit a compensatory increase in the anterior pelvic tilt during gait. Materials & Methods. Twelve patients were included in this prospective radiographic and gait analysis study prior to the PAO. All were women. The mean age was 27 years (+/− 8 yrs). Tonnis grade was zero in nine, and one in three hips. All patients performed multiple one-minute walking trials on the level, the incline, and the decline treadmill surfaces in an optical motion capture lab. Anterior pelvic tilt is reported in (+), while the posterior pelvic tilt is reported in (–) values. Results. Radiographic Data. : The mean alpha angle measured from the Dunn and the frog lateral images was 63.0º±17.4, and 54.7º±16.4, respectively. The mean LCEA was 14.9°±6.1, and the mean anterior center edge angle was 18.3°±8.9. the mean acetabular version at 1, 2, and 3 o'clock were 12.1°±11.6, 29.2°±9.9, and 23.3°±7.4, respectively. Intra-class correlation coefficient (ICC) for these measurements were 0.934, 0.895, and 0.971, respectively. The mean femoral anteversion, as measured on the 3D CT scan was 21.3°±16.1. The mean hip flexion range was 107.1°± 7.2. The mean pelvic tilt was 88.7 mm ± 14.4 using the PS-SI distance with an ICC of 0.998. Gait Data. : Baseline measurements were done in the standing position. On the leveled surface, 5 patients had anterior (+) while 7 had posterior (−) pelvic tilt. The mean posterior pelvic tilt was 1.0° with the range of −2.8° to +0.67°. On the inclined surface, all patients had posterior (−) pelvic tilt. The mean pelvic tilt was −4.9° with the range of −6.4° to −3.1°. On the declined surface, 8 patients had anterior (+) while 4 patients had posterior (−) pelvic tilt. The mean pelvic tilt was −0.39° with the range of −1.9° to +1.0°. The pelvic tilt was negatively correlated with the PS-SI distance on all three surfaces with the Spearman coefficients of −0.27, −0.04, and −0.18 on the 3 different surfaces, respectively. Conclusion. Our results demonstrated that the patients with hip dysplasia exhibit variable degrees of the pelvic tilt while walking on different surface inclinations. Weak negative correlation with the standing pelvic tilt measurements from the radiographs suggests that those patients with more anterior standing pelvic tilt tend to have greater compensatory posterior tilt during gait

Hypothesis. Recent advances in understanding of ACL insertional anatomy has led to new concepts of anatomical positioning of tunnels for ACL reconstruction. Femoral tunnel position has been defined in terms of the lateral intercondylar ridge and the bifurcate ridge but these can be difficult to identify at surgery. Measurements of the lateral wall either using C-arm x-ray control or specific arthroscopic rulers have also been advocated. Method. 30 patients undergoing ACL reconstruction before and after introduction of a new anatomical technique of ACL reconstruction were evaluated using 3D CT scan imaging with cut away views of the lateral aspect of the femoral notch and the radiological quadrant grid. In the new technique, with the knee at 90 degrees flexion, the femoral tunnel was centred 50% from deep to shallow as seen from the medial portal (Group A). Group B consisted of patients where the femoral tunnel was drilled through the antero-medial portal and offset from the posterior wall using a 5mm jig. Results. Ridges were identifiable in only 76% of scans. All tunnels in Group A (anatomical technique) were found to be below (posterior to) the lateral intercondylar (residents) ridge and were within 10% of the optimal position as defined by the Grid method on x-ray. No femoral tunnels in Group B meet anatomical criteria and were malpositioned by a mean of 5mm. Conclusion. We believe 3D CT scan imaging with cut away views of the femoral tunnel is a useful and accurate way of describing tunnel position, and that this technique will be valuable in validating new surgical techniques. According to this CT scan analysis the new anatomical technique correctly placed the femoral tunnel. This work forms the basis of a subsequent randomised trial of techniques in relation to clinical outcome

We evaluated the geometry of the resected femoral surface according to the theory for total knee arthroplasty (TKA) using three-dimensional computed tomography (3D CT). The 3D CT scans were performed in 44 knees indicated as requiring total knee arthroplasty. The 3D images of the femurs were clipped according to the following procedures. The distal femur was cut perpendicular to the mechanical axis at 10 mm proximal from the medial condyle. Rotational alignment was fixed at 3 degrees external rotation from the posterior condylar line. The anterior condyle was resected using the anterior cortex as the reference point. The posterior condyle was cut at 10 mm anterior from the medial posterior condyle. The medial-lateral (ML) width/anterior-posterior (AP) length was 1.58 ± 0.14 (mean ± SD). AP length of the 3D images tended to be longer than the box length of the three kinds of components provided when the ML width of the images was approximately equal to that of each component. The widths of medial and lateral posterior condyles of the images were 30.1 ± 3.8 mm and 24.8 ± 3.0 mm, respectively. In all except one case, the widths of the resected medial posterior condyles were greater than those of the medial condyles of all components when those of resected lateral posterior condyles were equal to those of the lateral condyles of the components. The shapes of the resected femoral surface did not always match those of the components. The configuration of Japanese knee joints is different from that of American knee joints. Components with appropriate geometry should be designed for Japanese patients

We present an analysis of manual and computer-assisted preoperative pedicle screw placement planning. Preoperative planning of 256 pedicle screws was performed manually twice by two experienced spine surgeons (M1 and M2) and automatically once by a computer-assisted method (C) on three-dimensional computed tomography images of 17 patients with thoracic spinal deformities. Statistical analysis was performed to obtain the intraobserver and interobserver variability for the pedicle screw size (i.e. diameter and length) and insertion trajectory (i.e. pedicle crossing point, sagittal and axial inclination, and normalized screw fastening strength). In our previous study, we showed that the differences among both manual plannings (M1 and M2) and computer-assisted planning (C) are comparable to the differences between manual plannings, except for the pedicle screw inclination in the sagittal plane. In this study, however, we obtained also the intraobserver variability for both manual plannings (M1 and M2), which revealed that larger differences occurred again for the sagittal screw inclination, especially in the case of manual planning M2 with average differences of up to 18.3°. On the other hand, the interobserver variability analysis revealed that the intraobserver variability for each pedicle screw parameter was, in terms of magnitude, comparable to the interobserver variability among both manual and computer-assisted plannings. The results indicate that computer-assisted pedicle screw placement planning is not only more reproducible and faster than, but also as reliable as manual planning

Background. This study was conducted to assess the clinical and radiologic results of total knee arthroplasty (TKA) with an allogenic bone graft using varus-valgus constrained (VVC) prostheses in knees with severe bone defects and unstable neuropathy. Methods. This study included 20 knees of 16 patients who underwent TKA between August 2001 and January 2006 due to unstable knees with severe bone destruction resulting from neuropathic arthritis. At the time of surgery, the mean age of the patients was 56 years. The mean length of the follow-up period was 10.7 years. A VVC condylar prosthesis was used with an allogenic femoral head graft to reconstruct large bony defects. Clinical results were evaluated using the Hospital for Special Surgery (HSS), Knee Society (KS) function, and Western Ontario and McMaster Universities Osteoarthritis (WOMAC) scores. Three-dimensional computed tomography (3D-CT) was used to evaluate the radiological parameters, which included the tibiofemoral angle, loosening or osteolysis of components, and incorporation of the bone graft. Results. The preoperative mean HSS, KS function, and WOMAC scores were 40.5, 43.2, and 78.3, respectively, and these scores improved to 86.0, 64.6, and 33.8 at the final follow-up. The mean postoperative alignment was 6.1° of valgus angulation. One knee had instability, another knee had partial bony absorption, which was confirmed using 3D-CT, and the other 18 cases (90%) had satisfactory results. No cases experienced radiolucency, fracture, or infection. Conclusions. TKA with an allogenic bone graft using a VVC prosthesis provides a viable option for the treatment of severe bone defects with soft tissue insufficiency in neuropathic knee arthropathy. Level of Study: Level IV, therapeutic study