To quantify the acetabular coverage of the femoral head, Lequesne's vertical-center-anterior edge (VCA) angle is used on the false profile view. Lateral coverage is determined by Wiberg's lateral-center-edge (LCE) angle on an ap pelvic view. The delimitation of the weightbearing area is defined by the end of the subchondral sclerosis line for both views. To our knowledge the exact anatomic location of the points used for measurement on the acetabular rim are not known. Six hips from three cadaver pelvises (3 male and 3 female) were investigated. The anterior and lateral points of interested were identified radiographically using fluoroscopy and marked with 1mm ceramic bullets. Standard false profile views and ap pelvic views in neutral inclination and rotation were taken to check the correct location of the ceramic bullets. A CT of each pelvis was made to locate the ceramic bullets and to define the exact anatomic location of the measurement points on the o'clock position. 6 o‘clock was defined as the midpoint between anteroinferior and the posteroinferior rim edges. Values were normalized for a right hip. The mean clockface location for the VCA was 1:33 (range, 1:15 to 1:40) and for the LCE 0:38 (range, 0:20 to 0:50). The LCEA is slightly anterior to the 12 o'clock position and remains useful to quantify the lateral coverage. Surprisingly, the point used for measuring the VCA is only about 30° (1h) anterior of the point used for measuring the LCEA. Its value for determining anterior cover has to be questioned. The discrepancy to other studies in the literature is because this study identifies and measures the end of the weight bearing zone, and not the border of the bony acetabulum

Aims. The complex relationship between acetabular component position and spinopelvic mobility in patients following total hip arthroplasty (THA) renders it difficult to optimize acetabular component positioning. Mobility of the normal lumbar spine during postural changes results in alterations in pelvic tilt (PT) to maintain the sagittal balance in each posture and, as a consequence, markedly changes the functional component anteversion (FCA). This study aimed to investigate the in vivo association of lumbar degenerative disc disease (DDD) with the PT angle and with FCA during postural changes in THA patients. Methods. A total of 50 patients with unilateral THA underwent CT imaging for radiological evaluation of presence and severity of lumbar DDD. In all, 18 patients with lumbar DDD were compared to 32 patients without lumbar DDD. In vivo PT and FCA, and the magnitudes of changes (ΔPT; ΔFCA) during supine, standing, swing-phase, and stance-phase positions were measured using a validated dual fluoroscopic imaging system. Results. PT, FCA, ΔPT, and ΔFCA were significantly correlated with the severity of lumbar DDD. Patients with severe lumbar DDD showed marked differences in PT with changes in posture; there was an anterior tilt (-16.6° vs -12.3°, p = 0.047) in the supine position, but a posterior tilt in an upright posture (1.0° vs -3.6°, p = 0.005). A significant decrease in ΔFCA during stand-to-swing (8.6° vs 12.8°, p = 0.038) and stand-to-stance (7.3° vs 10.6°,p = 0.042) was observed in the severe lumbar DDD group. Conclusion. There were marked differences in the relationship between PT and posture in patients with severe lumbar DDD compared with healthy controls. Clinical decision-making should consider the relationship between PT and FCA in order to reduce the risk of impingement at large ranges of motion in THA patients with lumbar DDD. Cite this article: Bone Joint J 2020;102-B(11):1505–1510

Introduction. Radiographic assessment of acetabular fragment positioning during periacetabular osteotomy (PAO) is of paramount importance. Plain radiographic examination is time and resource intensive. Fluoroscopic based assessment is increasingly utilized but can introduce distortion. Our purpose was to determine the correlation of intraoperative fluoroscopy-based measurements with a fluoroscopic tool that corrects for distortion with postoperative plain-film measurements. Methods. We performed a prospective validation study on 32 PAO's (28 patients) performed by a single academic surgeon. Preoperative standing radiographs, intraoperative fluoroscopic images, and postoperative standing radiographs were evaluated with lateral center edge angle (LCEA), acetabular index (AI), posterior wall sign (PWS), and anterior center edge angle (ACEA). Intraoperative fluoroscopy was adjusted to account for pelvic inclination. The fluoroscopic GRID was utilized in all cases (Phantom MSK Hip Preservation, OrthoGrid LLC, Salt Lake City, UT). Intraoperative fluoroscopic measurements were compared to preoperative and postoperative standing radiographs at 6 weeks using linear regression applied in MINITAB. Results. All pre and post-correction measurements demonstrated excellent agreement within an average difference of 1.2 and 0.9 degrees (deg) respectively (p<0.01). Agreement between post-correction fluoroscopic GRID measurements and 6-week postoperative radiographs was: average difference for LCEA −0.4 deg (range −5 to 8 deg, SD 3.4), −0.9 deg for ACEA (range −16 to 7 deg, SD 5.1), and 0.3 deg for AI (range −8 to 6 deg, SD 3.3) (all p<.01). The PWS agreement was 93%. There was a tendency for fluoroscopic GRID measurements to underestimate acetabular coverage by less than 1 degree. Conclusion. Our study validated the use of a novel intraoperative fluoroscopic tool that accounts for fluoroscopic distortion and permits real-time measurements of PAO fragment correction that correlate accurately with postoperative evaluation. We believe that this tool adds value by giving surgeons reliable quantitative measurements of correction without interfering with surgical work-flow. For any tables or figures, please contact the authors directly

Introduction. While additional resources associated with direct anterior (DA) approach total hip arthroplasty (THA) such as fluoroscopy, staff, and special tables are well recognized, time consumption is not well studied. The purpose of this study was to analyze anesthesia and surgical time in DA and posterior approach THA in a large healthcare system across multiple facilities and surgeons. Methods. 3,155 unilateral primary THAs performed via DA or posterior approaches between 1/1/2017 and 06/30/2019 at nine hospitals and ambulatory surgery centers (ASC) in a large metropolitan healthcare system were retrospectively reviewed. All surgeons were experienced and beyond learning curves. 247 cases were excluded to eliminate confounds. Operating room (OR) in and out times and surgical times were collected via EMR electronic and manual data extraction with verification. Multivariate statistical analyses were utilized with p<0.05 significant. Results. 1261 DA approach (43%) and 1647 posterior approach (57%) THAs were analyzed. Mean total OR time, including anesthesia and positioning, was greatest for hospital-based DA THAs (146 mins), followed by hospital posterior approach THAs (126.4 mins), ASC-based DA THAs (118.1 mins) and ASC posterior THAs (90.1 mins) (p<0.001). In multivariate analysis, compared to the optimal ASC posterior approach group, the total OR time predictive model added 31 minutes per ASC DA THA, 33 minutes per hospital posterior THA, and 56 minutes for hospital DA THA (p<0.001). Similar predictive effect was observed for surgical time, which added 18 minutes per ASC-based DA THA, 22 minutes for hospital posterior THA and 29 minutes for hospital DA THA (p<0.001). Conclusion. In the COVID era, efficiency should be enhanced to maximize patient access for elective procedures and facilitate the healthcare system financial recovery. Despite equivocal clinical results, DA approach THA consumes substantially more OR time when compared to the posterior approach in both the hospital and ASC setting

Aims

Total hip arthroplasty (THA) is considered the preferred treatment for displaced proximal femoral neck fractures. However, in many countries this option is economically unviable. To improve outcomes in financially disadvantaged populations, we studied the technique of concomitant valgus hip osteotomy and operative fixation (VOOF). This prospective serial study compares two treatment groups: VOOF versus operative fixation alone with cannulated compression screws (CCSs).

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When performing revision total hip arthroplasty using diaphyseal-engaging titanium tapered stems (TTS), the recommended 3 to 4 cm of stem-cortical diaphyseal contact may not be available. In challenging cases such as these with only 2 cm of contact, can sufficient axial stability be achieved and what is the benefit of a prophylactic cable? This study sought to determine, first, whether a prophylactic cable allows for sufficient axial stability when the contact length is 2 cm, and second, if differing TTS taper angles (2° vs 3.5°) impact these results.

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Although there are various pelvic osteotomies for acetabular dysplasia of the hip, shelf operations offer effective and minimally invasive osteotomy. Our study aimed to assess outcomes following modified Spitzy shelf acetabuloplasty.

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The aim of this study was to compare open reduction and internal fixation (ORIF) with revision surgery for the surgical management of Unified Classification System (UCS) type B periprosthetic femoral fractures around cemented polished taper-slip femoral components following primary total hip arthroplasty (THA).

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Successful cell therapy in hip osteonecrosis (ON) may help to avoid ON progression or total hip arthroplasty (THA), but the achieved bone regeneration is unclear. The aim of this study was to evaluate amount and location of bone regeneration obtained after surgical injection of expanded autologous mesenchymal stromal cells from the bone marrow (BM-hMSCs).

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The aims of this study were to characterize the incidence and risk factors associated with stress fractures following periacetabular osteotomy, and to determine their effect on osteotomy union.

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Lateral femoral cutaneous nerve (LFCN) injury is a potential complication after the direct anterior approach for total hip arthroplasty (DAA-THA). The aim of this study was to determine how the location of the fasciotomy in DAA-THA affects LFCN injury.

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This study reports mid-term outcomes after periacetabular osteotomy (PAO) exclusively in a borderline hip dysplasia (BHD) population to provide a contrast to published outcomes for arthroscopic surgery of the hip in BHD.

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It is important to analyze objectively the hammering sound in cup press-fit technique in total hip arthroplasty (THA) in order to better understand the change of the sound during impaction. We hypothesized that a specific characteristic would present in a hammering sound with successful fixation. We designed the study to quantitatively investigate the acoustic characteristics during cementless cup impaction in THA.

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It is important to analyze objectively the hammering sound in cup press-fit technique in total hip arthroplasty (THA) in order to better understand the change of the sound during impaction. We hypothesized that a specific characteristic would present in a hammering sound with successful fixation. We designed the study to quantitatively investigate the acoustic characteristics during cementless cup impaction in THA.

Background. Total hip arthroplasty requires proper sizing and placing of implants to ensure excellent outcomes and reduce complications. Calculation of femoral offset is an important consideration for optimal reconstruction of the hip biomechanics. Femoral offset can be measured on plain films or with flouroscopy if the x-ray beam is perpendicular to the plane determined by the angle between the neck axis and femoral shaft axis. This distance is evident only with the femur in the correct degree of rotation. Though pre-operative templating for femoral component size and offset is a regular accepted practice, a consistent method for assessing correct femoral rotation on the AP x-ray view has not been established. Purpose/Hypthesis. The purpose of the current study was to establish and validate a method for identifying radiographic landmarks on the proximal femur that would reliably indicate that the femur was in the proper degree of rotation to represent the true offset from the head center to shaft center. Methods. Lead markers were placed on areas of the greater trochanter followed by xrays. Markers placed on locations on the anterior and posterior greater trochanter duplicated reliable radiographic lines. Proximal femurs were dissected to the bone and rotated about their long axis from neutral rotation, defined at the point when the anterior and posterior aspects of the greater trochanter were aligned radiographically. Radiographs were taken at 2 degree increments in both internal and external rotation until 10 degrees, then again at 30 degrees. A custom script was used to calculate the femoral offset at these rotations at these locations. Descriptive analysis was performed to assess the relationship between rotation angle and femoral offset. Results. The mean femoral offset was observed to be 38.21 mm (SD 4.93, median 37.82, range 30.52–46.27). The mean rotation of max offset was −3.6° (SD 5.6, median −6, range −10 to +8). The average underestimation error (the difference between calculated offset at neutral rotation and observed maximum femoral offset) was 0.92 mm (median 0.74, range 0 to 2.07 mm). Conclusion. Alignment of the radiographic lines created by the anterior and posterior aspects of the greater trochanter is a reliable and accurate rotational positioning method for measuring femoral offset when using plain films or fluoroscopy. It is a feasible method that can be applied preoperatively and/or intraoperatively to optimize accuracy of femoral offset for THA procedures. For any tables or figures, please contact the authors directly

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Hip arthroscopy has gained prominence as a primary surgical intervention for symptomatic femoroacetabular impingement (FAI). This study aimed to identify radiological features, and their combinations, that predict the outcome of hip arthroscopy for FAI.

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Femoroacetabular impingement (FAI) patients report exacerbation of hip pain in deep flexion. However, the exact impingement location in deep flexion is unknown. The aim was to investigate impingement-free maximal flexion, impingement location, and if cam deformity causes hip impingement in flexion in FAI patients.

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Adverse spinal motion or balance (spine mobility) and adverse pelvic mobility, in combination, are often referred to as adverse spinopelvic mobility (SPM). A stiff lumbar spine, large posterior standing pelvic tilt, and severe sagittal spinal deformity have been identified as risk factors for increased hip instability. Adverse SPM can create functional malposition of the acetabular components and hence is an instability risk. Adverse pelvic mobility is often, but not always, associated with abnormal spinal motion parameters. Dislocation rates for dual-mobility articulations (DMAs) have been reported to be between 0% and 1.1%. The aim of this study was to determine the early survivorship from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) of patients with adverse SPM who received a DMA.

Introduction. As new innovations are developed to improve the longevity of joint replacement components, preclinical testing is necessary in the early stages of research into areas such as osseointegration, metal-cartilage wear and periprosthetic joint infection (PJI). Large-animal studies that test load-bearing components are expensive, however, requiring that animals be housed in special facilities that are not available at all institutions. Comparably, small animal models, such as the rat, offer several advantages including lower cost. Load-bearing implants remain difficult to manufacture via traditional methods in the sizes required for small-animal testing. Recent advances in additive manufacturing (3D metal-printing) have allowed for the creation of miniature joint replacement components in a variety of medical-grade metal alloys. The objective of this work is to create and optimize an image-based 3D-printed rat hip implant system that will allow in vivo testing of functional implant properties in a rat model. Methods. A database of n=25 previously-acquired, 154μm micro-CT volumes (eXplore Locus Ultra, GE Medical) of male Sprague-Dawley rats (390–610g) were analyzed to obtain spatial and angular relationships between several anatomical features of the proximal rat femora. Mean measurements were used to guide the creation of a femoral implant template in computer-aided design software (Solidworks, Dassault Systemes). Several different variations were created, including collarless and collared designs, in a range of sizes to accommodate rats of various weights. Initial prototypes were 3D-printed 316L stainless steel with subsequent iterations printed in Ti6Al4V titanium and F75 cobalt-chrome. Implants were post-processed via sandblasting, hand-polishing, ultrasonic bath, and sterilization in an autoclave. Innate surface texturing was left on manufactured stems to promote osseointegration. Surgical implantation was performed in three live Sprague-Dawley rats (900g, 500g, 750g) with preservation of muscle attachments to the greater trochanter. Micro-CT imaging and X-ray fluoroscopy were performed post-operatively on each animal at 1 day, and 1, 3, 9 and 12 weeks to evaluate gait and component positioning. Results. Implantation of components was successful and each animal was observed to ambulate on its affected limb immediately following recovery from surgery. The 900g rat, given a collarless 316L stainless steel component, was kept for 11 months post-implantation before succumbing to old age. Micro-CT and fluoroscopic findings revealed no evidence of implant subsidence. The 500g animal, given a collarless 316L stainless steel implant, showed evidence of implant subsidence at 3 weeks, with full subsidence and hip dislocation at 12 weeks. The 750g rat, given a collared F75 cobalt-chrome implant, was observed ambulating on its affected limb, but experienced implant rotation and failure at 9 weeks. Conclusions. We report the first hip hemi-arthroplasty in a rat using a 3D-printed metal implant. This model aims to provide a low-cost platform for studying osseointegration, metal-cartilage interactions, and PJI using a functional, loaded implant. Efforts to further optimize the surgical approach will be made to reduce early implant loosening. A study with larger sample sizes is needed to determine if implants can be installed repeatedly, without complications, before the utility of this approach can be validated. Future work will include surface preparations on implant stems, with micro-CT to longitudinally track changes at the bone-metal interface, and gait analysis on a radiolucent treadmill to quantify post-operative kinematics

Aims

There is evidence that morbidly obese patients have more intra- and postoperative complications and poorer outcomes when undergoing total hip arthroplasty (THA) with the direct anterior approach (DAA). The aim of this study was to determine the efficacy of DAA for THA, and compare the complications and outcomes of morbidly obese patients with nonobese patients.