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)

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

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

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

Introduction. Malpositioning of the acetabular cup during total hip arthroplasty increases the risk of dislocation, edge loading, squeaking and can be responsible for early wear and loosening. We hypothesized that the use of three-dimensional visualization tools showing during surgery the planned cup position relatively to the acetabular edge would increase the accuracy of cup orientation. The purpose of this study was to compare 3D planning-assisted with freehand insertion of the acetabular cup. Methods. A randomized, controlled, prospective study of two groups of twenty eight patients each was performed. In the first group, cup positioning was guided by 3D views of the cup within the acetabulum based on a three-dimensional preoperative planning (Figure 1). In the control group, the cup was placed freehand. All of the patients were operated on by the same surgeon through a direct anterior approach in supine position. Cup anteversion and abduction angles were measured on three-dimensional computed tomography reconstructions for each patient by an independent observer. We analyzed the accuracy of both methods. The main evaluation criterion was the percentage of outliers according to the Lewinneck safe zone. Results. There was no difference in surgery time between the two groups. The cup anteversion angle was restored with a higher accuracy in the 3D-assisted group (−2.7 ± 5.4°) comparatively to the freehand-placement group (6.6 ± 9.5°, p<0.0008) (Figure 2). The percentage of outliers was twice lower in the 3D guided group (21%, 6 patients) comparatively to the control group (46%, thirteen of twenty eight p=0.04). According to the Callanan safe zone, the percentage of outliers was also lower in the 3D guided group (32%, versus 75%, p = 0.001) (Figure 3). The surgeon tends to position the cup with a higher anteversion than the native acetabulum anteversion. Conclusions. The use of a 3D preoperative planning can improve cup positioning in total hip arthroplasty by increasing the accuracy of the anteversion restoration and reducing the percentage of outliers. When using a direct anterior approach in supine position, the surgeon may tend intuitively to implant the cup with a higher anteversion value comparatively to the native acetabulum anteversion because of the postero-caudal overcoverage of the cup that gives a false impression of cup retroversion

Introduction. In the evaluation of patients with pre-arthritic hip disorders, making the correct diagnosis and identifying the underlying bone pathology is of upmost importance to achieve optimal patient outcomes. 3-dimensional imaging adds information for proper preoperative planning. CT scans have become the gold standard for this, but with the associated risk of radiation exposure to this generally younger patient cohort. Purpose. To determine if 3D-MR reconstructions of the hip can be used to accurately demonstrate femoral and acetabular morphology in the setting of femoroacetabular impingement (FAI) and development dysplasia of the hip (DDH) that is comparable to CT imaging. Materials and Methods. We performed a retrospective review of 14 consecutive patients with a diagnosis of FAI or DDH that underwent both CT and MRI scans of the same hip with 3D reconstructions. 2 fellowship trained musculoskeletal radiologists reviewed all scans, and a fellowship trained hip preservation surgeon separately reviewed scans for relevant surgical parameters. All were blinded to the patients' clinical history. The 3D reconstructions were evaluated by radiologists for the presence of a CAM lesion and acetabular retroversion, while the hip preservation surgeon also evaluated CAM extent using a clock face convention of a right hip, location of femoral head blood supply, and morphological anterior inferior iliac spine (AIIS) variant. The findings on the 3D CT reconstructions were considered the reference standard. Results. Of 14 patients, there were 9 females and 5 males with a mean age 32 (range 15–42). There was no difference in the ability of MRI to detect the presence of a CAM lesion (100% agreement between 3D-MR and 3D-CT, p=1), AIIS morphology (p=1, mode=type 1 variant), or acetabular retroversion (85.7%, p=0.5). 3D-MR had a sensitivity and specificity of 100 in detecting a CAM lesion relative to 3D-CT. Four CT studies were inadequate to adequately evaluate for presence of a CAM. Five CT studies were inadequate to evaluate for location of the femoral head vessels, while MRI was able to determine location in those patients. In the 10 remaining patients for presence of CAM, and nine patients for femoral head vessel location, there was no statistically significant difference between 3D-MR and 3D-CT in determining the location of CAM lesion on a clock face (p=0.8, mean MRI = 12:54, mean CT: 12:51, SD = 66 mins MR, 81 mins CT) or in determining vessel location (p=0.4, MR mean 11:23, CT mean 11:36, SD 33 mins for both). Conclusion. 3D MRI reconstructions are as accurate as 3D CT reconstructions in evaluating osseous morphology of the hip, and may be superior to CT in determining other certain clinically relevant hip parameters. 3D-MR was equally useful in determining the presence and extent of a CAM lesion, acetabular retroversion, and AIIS morphologic variant, and more useful than 3D CT in determining location of the femoral head vessels. In evaluating FAI or hip dysplasia, a 3D-MR study is sufficient to evaluate both soft tissue and osseous anatomy, sparing the need for a 3D CT scan and its associated radiation exposure and cost

Introduction:. The lateral radiographs are useful in evaluation of the acetabular cup anteversion. However, this method was affected by variations in pelvic position and radiographic technique. In this study, we employed the ischial axis (IA) as an anatomical landmark on the lateral radiographs, and we investigated a relationship between IA and the anterior pelvic plane (APP) using three-dimensional computed tomography (3D-CT). Using these findings, we report a new method for accurate measurement of the acetabular cup anteversion on plain lateral radiographs using IA as an anatomical reference. Materials and Methods:. At first, preoperative3D-CT images were obtained in 109 patients who underwent total hip arthroplasty. The diagnosis was osteoarthritis in all patients. The angle between the IA (defined by a line connecting the anterior edge of the greater sciatic notch and the lesser sciatic notch) and APP (defined by the bilateral anterosuperior iliac spine and the symphysis) was measured on 3D-CT (Fig. 1). Secondly, postoperative lateral radiographs were obtained at 2 weeks, 4 weeks, 12 weeks, 24 weeks, and 52 weeks after surgery in 15 patients. The angle between a line tangential to the opening of the cup and a line perpendicular to APP was measured (Fig. 2). Three methods of acetebular cup position assessment were compared: 1) the present method, 2) Woo and Morrey method, and 3) software (2D template, Kyocera) method. Results:. The mean angle between IA and APP was 18.0 ± 3.5°. The mean acetabular cup anteversion measured using present method was 21.3°, Woo and Morrey method was 26.6°, and software method was 21.2°. The mean SDs of present method was 0.64°, Woo and Morrey method was 1.17°, and software method was 0.46°. Conclusions:. APP, considered as vertical in weight bearing, has a relatively consistent relationship between IA. The findings of this study provide a more consistent measurement of acetabular cup by reducing variation due to pelvic position

This RCT compared electromagnetic (EM) navigated and conventional total knee arthroplasty (TKA) in terms of clinical and functional outcomes. 200 patients (navigated=102, conventional=98) were recruited. Oxford Knee Scores (OKS) and the American Knee Society Score (AKSS) were recorded pre operation, 3 and 12 months after surgery. Post operative (coronal, sagittal and rotational) alignment was analysed from 3D CT scans taken 3 months after surgery. An objective functional assessment was completed using electrogoniometry on a sub group (navigated=60, conventional=57) at 12 months post surgery. The EM group showed statistically significantly improved OKS (p=0.04) and AKSS (p=0.03) scores at 3 months post operation. However at 12 months post surgery there was no difference between the two groups. At the 1 year follow up it was reported that 9% of the navigated compared to 14% of the conventional group were dissatisfied with their surgical outcome. The mechanical axis alignment of 90% of the navigated group was within 3 degrees of neutral compared to 84% of the conventional group. Although all alignment parameters except for tibial rotation was improved in the navigated group they did not reach significance apart from femoral slope alignment (p=0.01). There was no statistically difference between the surgical groups in terms of the maximum, minimum and excursion knee joint angles during 12 functional activities. Only the knee kinematic function cycles for level walking resulted in statistically significant higher knee joint angles during 55–70% of the gait cycle in the navigated group. Knee alignment was better restored following EM navigated TKA relative to conventional TKA, but the difference was not significant. The EM group showed greater clinical and functional improvements at early follow-up; however this difference was not sustained at 12 months. The EM group reported minimal gait improvements. Proving cost-effectiveness for navigation systems in TKA remains a challenge

Background:. Acetabular component malpositioning in total hip arthroplasty increases the risk of dislocations, impingement, and long-term component wear. The purpose of this Sawbones study was to define the efficacy of a novel acetabular imprinting device (AID) with 3D preoperative planning in accurately placing the acetabular component. Methods:. Four surgeons performed the study on osteoarthritic and dysplastic Sawbone models using 3 different methods for placing the acetabular component (total n = 24). The 3 methods included (1) standard preoperative planning and instrumentation (i.e., standard method), (2) 3D computed tomographic (CT) scan planning and standard instrumentation (i.e., 3D planning method), and (3) 3D CT scan planning combined with an acetabular imprinting device (i.e., AID method). In the AID method, 3D planning software was used to virtually place the acetabular component at 40° of inclination and 22° of anteversion and create a parallel guide pin trajectory. A patient-specific surrogate bone model with a built-in guide pin trajectory was then manufactured as a stereoltihography device (Fig. 1A). The surgeon molded bone cement into the acetabulum imprinting the acetabular features while maintaining the guide pin trajectory (Fig. 1B). Afterward, the AID was removed from the surrogate bone model and placed onto the Sawbone, ensuring a secure fit (Fig. 1C). A guide pin was drilled into the Sawbone along the prescribed trajectory. With the guide pin in place, the surgeon could ream the acetabulum and impact the acetabular component using the guide pin as a visual aid (Fig. 1D). Postoperatively, a CT scan was used to define and compare the actual implant location with the preoperative plan. Statistical analysis was performed as 3 group comparisons using the chi-squared test for categorical data and analysis of variance (ANOVA) for continuous measurements. Results:. The AID method significantly decreased the mean deviation of acetabular component inclination (3.4°) compared to standard (14.0°) and 3D planning methods (17.4°) (p = 0.003). The mean deviation in version was 10.6° in the standard method, 10.8° in the 3D planning method, and 5.3° in the AID method (p = 0.28). Overall, AID reduced the number of implants malpositioned in excess of 10° from the planned position to 12.5%, compared with 87.5% in the standard method and 75% in the 3D planning method (p = 0.005) (Fig. 2). Conclusions:. Novel 3D preoperative planning combined with AID allows the surgeon to accurately replicate the preoperative plan using Sawbones models. This proof-of-concept study justifies a clinical trial to compare the AID to standard surgical techniques