Influence of hip prosthesis position on postoperative gait in symptomatic hip osteoarthritis secondary to hip dysplasia patients after primary total hip arthroplasty: a short-term follow-up study.

BACKGROUND: The aim of this study was to analyze the influence of the positioning of the components of total hip arthroplasty (THA) evaluated by the acetabular anteversion (AA) and femoral anteversion (FA) angle on postoperative gait in patients with symptomatic hip osteoarthritis secondary to hip dysplasia undergoing THA. METHODS: Between May 2023 and May 2024, patients with symptomatic hip osteoarthritis secondary to hip dysplasia (Crowe Type I and IV) who underwent THA were enrolled in the study. The AA angle and FA angle were measured by computer tomography (CT). Gait data were determined by using the Dynamic Right Gait & Posture analysis system. The relationship between FA, AA and gait data was analyzed by Pearson correlation test, subgroup Pearson correlation test, multiple linear regression. RESULTS: A total of 40 patients (45hips) were included in the study. Compared with preoperative, the patient's postoperative foot progression angle, foot contact angle, plantarflexion velocity, swing foot speed, gait velocity, cadence, stride length were significantly improved. Preoperative FA is significantly different from postoperative FA (P < 0.05), while the difference between preoperative and postoperative AA is not significant. BMI, Crowe Type, AA were related to change of cadence. The less the postoperative AA of patients, and the more the cadence in the postoperative gait of patients. CONCLUSION: Our study showed that THA could improve the gait function of patients with symptomatic hip osteoarthritis secondary to hip dysplasia. Adjusting AA lower could obtain a much more postoperative cadence.

Do 3-dimensional Spinopelvic Characteristics Normalize After THA? A Prospective, Comparative Study Using Motion Capture Analysis.

BACKGROUND: Spinopelvic stiffness (primarily in the sagittal plane) has been identified as a factor associated with inferior patient-reported outcomes (PROs) and increased dislocation risk after THA. Incorporating preoperative spinopelvic characteristics into surgical planning has been suggested to determine a patient-specific cup orientation that minimizes dislocation risk. Sagittal plane radiographic analysis of static postures indicates that patients exhibit a degree of normalization in their spinopelvic characteristics after THA. It is not yet known whether normalization is also evident during dynamic movement patterns, nor whether it occurs in the coronal and axial planes as well. QUESTIONS/PURPOSES: (1) Does motion capture analysis of sagittal spinopelvic motion provide evidence of normalization after THA? (2) Do changes in coronal and axial plane motion accompany those in the sagittal plane? METHODS: Between April 2019 and February 2020, 25 patients agreed to undergo motion capture movement analysis before THA for the treatment of hip osteoarthritis (OA). Of those, 20 underwent the same assessment between 8 and 31 months after THA. Five patients were excluded because of revision surgery (n = 1), contralateral hip OA (n = 1), and technical issues with a force plate during post-THA assessment (n = 3), leaving a cohort total of 15 (median age [IQR] 65 years [10]; seven male and eight female patients). A convenience sample of nine asymptomatic volunteers, who were free of hip and spinal pathology, was also assessed (median age 51 years [34]; four male and five female patients). Although the patients in the control group were younger than those in the patient group, this set a high bar for our threshold of spinopelvic normalization, reducing the possibility of false positive results. Three-dimensional motion capture was performed to measure spinal, pelvic, and hip motion while participants completed three tasks: seated bend and reach, seated trunk rotation, and gait on a level surface. ROM during each task was assessed and compared between pre- and post-THA conditions and between patients and controls. Statistical parametric mapping (SPM) was used to assess the timing of differences in motion during gait, and spatiotemporal gait parameters were also measured. RESULTS: After THA, patients demonstrated improvements in sagittal spinal (median [IQR] 32° [18°] versus 41° [14°]; difference of medians 9°; p = 0.004), pelvis (25° [21°] versus 30° [8°]; difference of medians 5°; p = 0.02), and hip ROM (21° [18°] versus 27° [10°]; difference of medians 6°; p = 0.02) during seated bend and reach as well in sagittal hip ROM during gait (30° [11°] versus 44° [7°]; difference of medians 14°; p < 0.001) compared with their pre-THA results, and they showed a high degree of normalization overall. These sagittal plane changes were accompanied by post-THA increases in coronal hip ROM (12° [9°] versus 18° [8°]; difference of medians 6°; p = 0.01) during seated trunk rotation, by both coronal (6° [4°] versus 9° [3°]; difference of medians 3°; p = 0.01) and axial (10° [8°] versus 16° [7°]; difference of medians 6°; p = 0.003) spinal ROM, as well as coronal (8° [3°] versus 13° [4°]; difference of medians 5°; p < 0.001) and axial hip ROM (21° [11°] versus 34° [24°]; difference of medians 13°; p = 0.01) during gait compared with before THA. The SPM analysis showed these improvements occurred during the late swing and early stance phases of gait. CONCLUSION: When restricted preoperatively, spinopelvic characteristics during daily tasks show normalization after THA, concurring with previous radiographic findings in the sagittal plane. Thus, spinopelvic characteristics change dynamically, and incorporating them into surgical planning would require predictive models on post-THA improvements to be of use. LEVEL OF EVIDENCE: Level II, prognostic study.

The relationship between MRI-detected hip abnormalities and hip pain in hip osteoarthritis: a systematic review.

Magnetic resonance imaging (MRI) is increasingly used in the classification and evaluation of osteoarthritis (OA). Many studies have focused on knee OA, investigating the association between MRI-detected knee structural abnormalities and knee pain. Hip OA differs from knee OA in many aspects, but little is known about the role of hip structural abnormalities in hip pain. This study aimed to systematically evaluate the association of hip abnormalities on MRI, such as cartilage defects, bone marrow lesions (BMLs), osteophytes, paralabral cysts, effusion-synovitis, and subchondral cysts, with hip pain. We searched electronic databases from inception to February 2024, to identify publications that reported data on the association between MRI features in the hip joint and hip pain. The quality of the included studies was scored using the Newcastle-Ottawa Scale (NOS). The levels of evidence were evaluated according to the Cochrane Back Review Group Method Guidelines and classified into five levels: strong, moderate, limited, conflicting, and no evidence. A total of nine studies were included, comprising five cohort studies, three cross-sectional studies, and one case-control study. Moderate level of evidence suggested a positive association of the presence and change of BMLs with the severity and progress of hip pain, and evidence for the associations between other MRI features and hip pain were limited or even conflicting. Only a few studies with small to modest sample sizes evaluated the association between hip structural changes on MRI and hip pain. BMLs may contribute to the severity and progression of hip pain. Further studies are warranted to uncover the role of hip MRI abnormalities in hip pain. The protocol for the systematic review was registered with PROSPERO ( https://www.crd.york.ac.uk/PROSPERO/ , CRD42023401233).

Characteristics of pelvic obliquity in dysplastic hip osteoarthritis.

PURPOSE: Factors affecting direction of pelvic obliquity (PO) in dysplastic hip osteoarthritis (DHOA) remains unclear. This retrospective cohort study evaluates morphological characteristics, spinal alignment, and hip function in patients with unilateral DHOA. METHODS: Between 2018 and 2022, 104 patients with unilateral DHA were enrolled. Patients were categorized into flat PO (F-PO group; PO < 2°), affected side PO (A-PO group; PO downward by ≥ 2°), and unaffected side PO (U-PO group; PO upward by ≥ 2°). Demographics, radiographic hip and lower limb parameters, spinal parameters, and functional scores were compared between the groups. RESULTS: There were 39, 44, and 21 patients in the F-PO, A-PO, and U-PO group, respectively. The subluxation percentage of Crowe classification showed a significant difference among the three groups. The femoral head lateralization distance was significantly greater in the U-PO group than in the F-PO and A-PO groups. Furthermore, the hip adduction angle was significantly lower in the A-PO group than in the F-PO and U-PO groups. The lumbar scoliosis angle was significantly different between the groups. In multivariate analysis, hip adduction angle was extracted as an independent factor associated with the A-PO. Age, subluxation percentage, and hip adduction angle were identified as independent factors associated with the U-PO. Harris hip score was significantly poorer in U-PO group than in F-PO group. CONCLUSIONS: Hip adduction angle influenced A-PO, while age, subluxation percentage, and hip adduction angle influenced U-PO; lumbar scoliosis angle was associated with PO direction. U-PO patients had poorer functional scores, indicating the impact of hip contracture and subluxation on PO direction in DHOA.

A Study on Imaging Risk Factors for Hip Osteoarthritis.

OBJECTIVE: Due to low prevalence and few studies, the morphologic risk factors for hip osteoarthritis (HOA) in Chinese population remain unknown. The purpose of this study was to investigate the relationship between 10 radiographic parameters measured via anteroposterior pelvic X-ray radiography and HOA in Chinese population. METHODS: Thirty-three patients who required total hip arthroplasty for unilateral HOA (2017-2022) and 132 healthy individuals were selected for this case-control study. We measured 10 radiological parameters via anteroposterior pelvic X-ray radiography, which were sharp angle, center edge angle, sourcil angle, neck shaft angle, α angle, pelvic height, pelvic width, femoral head diameter, femoral neck width, and ratio of the femoral head diameter to the femoral neck width. After measurements were obtained, logistic regression analysis was utilized to calculate the adjusted odds ratios (ORs) for confounding variables such as age, sex, and body mass index (BMI). Receiver operating characteristic (ROC) curves were utilized to determine the proportional risk contribution (PRC) of each radiographic factor. RESULTS: After adjustment for confounding factors, individuals with a larger sourcil angle (SA) (OR = 4.89, 95% CI 1.66-14.42, p = 0.004), larger α angle (OR = 4.14, 95% CI 1.53-11.23, p = 0.005), and wider femoral neck (OR = 5.27, 95% CI 1.50-18.51, p = 0.01) were found to have a greater risk of developing HOA. Among all radiographic parameters, the SA demonstrated the greatest risk contribution (PRC = 13.695%). CONCLUSIONS: Radiographic parameters correlate with the incidence of HOA. The SA is probably the most powerful of all the parameters related to HOA.

Combined assessment of acetabular coverage and femoral head-neck shapes predicts osteoarthritis progression after periacetabular osteotomy.

INTRODUCTION: Postoperative osteoarthritis (OA) progression is a major determinant of failure after curved periacetabular osteotomy (CPO). A large postoperative combination angle, i.e., the combination of computed tomography-based anterior center edge and alpha angles, is associated with femoroacetabular impingement after CPO, but its association with postoperative OA progression is unclear. We aimed to identify the anatomical parameters that can lead to OA progression after CPO and the impact of the combination angle on the same. MATERIALS AND METHODS: We included 90 hips that were subjected to CPO at our center between March 2013 and March 2018. Seventeen hips showed OA progression with an increase in the Tönnis classification after surgery; 73 hips showed no progression. Radiographic anatomical parameters, including the lateral and anterior center edge angles, femoral and acetabular anteversion, and combination angle, and clinical outcomes, including modified Harris Hip Scores (mHHSs), postoperative anterior impingement, and range of motion, were compared between the two groups. Statistical significance was set at P < 0.05. RESULTS: Postoperative OA progression was significantly affected by preoperative OA evidence (P = 0.017), acetabular anteversion < 5.0° (P = 0.003), and a combination angle > 107.0° (P = 0.025). Patients with radiographic OA progression were associated with poor mHHSs (P = 0.017) and high frequencies of anterior impingement with a limited hip flexion and internal rotation angle. CONCLUSIONS: OA progression after CPO may be associated with preoperative evidence of OA and postoperative acetabular retroversion as well as a large combination angle. Surgeons should focus on the potential effects of preoperative OA grades, postoperative reduction in acetabular anteversion, and postoperative combination angle.

Finite element analysis of mechanical stress in a cementless tapered-wedge short stem in the varus position.

BACKGROUND: In recent years, the use of tapered-wedge short stems has increased due to their ability to preserve bones and tendons. Surgical techniques occasionally result in a varus position of the stem, which is particularly pronounced in short stems. Although the varus position is not clinically problematic, there are reports of an increased incidence of stress shielding and cortical hypertrophy. Thus, we evaluated and examined the acceptable range of varus angles using finite element analysis. METHODS: Patients diagnosed with osteoarthritis of the hip joint who had undergone arthroplasty were selected and classified into three types [champagne-flute (type A), intermediate (type B), and stovepipe (type C)]. Finite element analysis was performed using Mechanical Finder. The model was created using a Taperloc microplasty stem with the varus angle increased by 1° from 0° to 5° from the bone axis and classified into seven zones based on Gruen's zone classification under loading conditions in a one-leg standing position. The volume of interest was set, the mean equivalent stress for each zone was calculated. RESULTS: A significant decrease in stress was observed in zone 2, and increased stress was observed in zones 3 and 4, suggesting the emergence of a distal periosteal reaction, similar to the results of previous studies. In zone 2, there was a significant decrease in stress in all groups at a varus angle ≥ 3°. In zone 3, stress increased from ≥ 3° in type B and ≥ 4° in type C. In zone 4, there was a significant increase in stress at varus angles of ≥ 2° in types A and B and at ≥ 3° in type C. CONCLUSION: In zone 2, the varus angle at which stress shielding above Engh classification grade 3 may appear is expected to be ≥ 3°. Distal cortical hypertrophy may appear in zones 3 and 4; the narrower the medullary cavity shape, the smaller the allowable angle of internal recession, and the wider the medullary cavity shape, the wider the allowable range. Long-term follow-up is required in patients with varus angles > 3°.

Factors associated with joint survival after transposition osteotomy of the acetabulum in patients with Tönnis grade 2 osteoarthritis secondary to hip dysplasia.

Aims: The aim of this study was to determine the clinical outcomes and factors contributing to failure of transposition osteotomy of the acetabulum (TOA), a type of spherical periacetabular osteotomy, for advanced osteoarthritis secondary to hip dysplasia. Methods: We reviewed patients with Tönnis grade 2 osteoarthritis secondary to hip dysplasia who underwent TOA between November 1998 and December 2019. Patient demographic details, osteotomy-related complications, and the modified Harris Hip Score (mHHS) were obtained via medical notes review. Radiological indicators of hip dysplasia were assessed using preoperative and postoperative radiographs. The cumulative probability of TOA failure (progression to Tönnis grade 3 or conversion to total hip arthroplasty) was estimated using the Kaplan-Meier product-limited method. A multivariate Cox proportional hazards model was used to identify predictors of failure. Results: This study included 127 patients (137 hips). Median follow-up period was ten years (IQR 6 to 15). The median mHHS improved from 59 (IQR 52 to 70) preoperatively to 90 (IQR 73 to 96) at the latest follow-up (p < 0.001). The survival rate was 90% (95% CI 82 to 95) at ten years, decreasing to 21% (95% CI 7 to 48) at 20 years. Fair joint congruity on preoperative hip abduction radiographs and a decreased postoperative anterior wall index (AWI) were identified as independent risk factors for failure. The survival rate for the 42 hips with good preoperative joint congruity and a postoperative AWI ≥ 0.30 was 100% at ten years, and remained at 83% (95% CI 38 to 98) at 20 years. Conclusion: Although the overall clinical outcomes of TOA in patients with advanced osteoarthritis are suboptimal, favourable results can be achieved in selected cases with good preoperative joint congruity and adequate postoperative anterior acetabular coverage.

Bisphosphonates show no association with preventing, slowing, or delaying radiographic changes and pain in hip osteoarthritis: A 4-year study in female adults using data from the Osteoarthritis Initiative Study.

OBJECTIVE: This study aimed to investigate the association of bisphosphonates with outcomes related to radiographic changes and pain in hip osteoarthritis (OA) over 4 years. METHODS: This study examined data from the Osteoarthritis Initiative (OAI), which included 4088 hips from 2057 participants. Bisphosphonate users were identified as those who reported usage at least three times, including at baseline and during the subsequent 1, 2, 3, and 4-year follow-up visits. Non-users were participants who did not use bisphosphonates in the 5 years preceding the baseline and at subsequent follow-up visits. Generalized estimating equations were performed to assess the association between bisphosphonate use and outcomes related to radiographic changes and pain in hip OA over a 4-year follow-up. RESULTS: The analysis revealed no statistically significant difference between bisphosphonate users and non-users concerning outcomes related to radiographic changes and pain in hip OA over 4 years. Specifically, the odds ratios for the incidence and transition of radiographic hip OA were 0.55 (95% Confidence Interval [CI]: 0.26 to 1.17) and 0.78 (95% CI: 0.47 to 1.28), respectively. Furthermore, the odds ratios for the development and resolution of frequent hip pain were 1.04 (95% CI: 0.76 to 1.42) and 0.99 (95% CI: 0.72 to 1.36), respectively. CONCLUSION: The findings from this longitudinal study do not suggest an association between bisphosphonate use and the prevention, slowing, or delay of development and transition of radiographic changes or pain in hip OA over a 4-year follow-up.

Rapidly destructive hip osteoarthritis: a diagnosis not to miss.

This review illustrates the imaging features of rapidly destructive hip osteoarthritis (RDHO) across different imaging modalities. RDHO is a rare joint disease of unknown aetiology resulting in rapid deterioration of the hip joints. Patients often present with severe hip pain and can progress to complete joint destruction in 6 months to 3 years causing disability. Since its clinical and imaging features often overlap with other conditions, the diagnosis is easily missed in daily practice. The purpose of this paper is to outline the characteristic imaging features of RDHO, aiming to enhance awareness of this disease entity and promote timely treatment for patients. Sequential radiographs are particularly important in demonstrating the rapid progression of radiographic findings and with the early recognition of characteristic features, diagnosis can be made to avoid treatment delay. Although CT scan is not necessary for diagnosis, it is useful in evaluating the extent of joint destruction and guiding surgical planning. MRI can provide additional information and rule out other pathologies with similar symptoms. Overall, radiographs, CT and MRI are common modalities used in the evaluation of RDHO.

Decrease in pelvic incidence after adult spinal deformity surgery is a predictive factor for progression of hip joint osteoarthritis.

BACKGROUND: This study aimed to evaluate the association between spinopelvic alignment parameters and hip osteoarthritis progression after spinal alignment correction surgery for adult spinal deformity, focusing on the preoperative to postoperative change in spinopelvic alignment. METHODS: This retrospective study enrolled 100 adult spinal deformity patients (196 hip joints) who underwent spinal fusion surgery, after excluding four joints with previous total hip arthroplasty. Acetabular roof obliquity (ARO), center edge angle (CE) and Kellgren and Lawrence (KL) grade were measured in the hip joint. Spinopelvic alignment parameters were measured preoperatively and 1-month postoperatively and the changes (Δ) during this period were calculated. Patients were followed-up for ≥ 5 years and factors associated with KL grade progression at 5-years postoperatively were determined by logistic regression analysis. RESULTS: In the analysis with all cases, KL grade progressed in 23 joints. Logistic regression analysis revealed age (OR: 1.098, 95% CI: 1.007-1.198, p = 0.019), ARO (OR: 1.176, 95% CI: 1.01-1.37, p = 0.026), and Δ PI (OR: 0.791, 95% CI: 0.688-0.997, p < 0.001) as parameters significantly associated with KL grade progression. On the other hand, in the analysis limited to 185 cases with 1-month postoperative KL grade of 0, KL grade progressed in 13 joints. Logistic regression analysis revealed PI-LL (OR: 1.058, 95% CI: 1.001-1.117, p = 0.04), ΔPI (OR: 0.785, 95% CI: 0.649-0.951, p < 0.001), and ΔCobb (OR: 1.127, 95% CI: 1.012-1.253, p = 0.009) as parameters significantly associated with progression. CONCLUSIONS: Both the overall and limited analyzes of this study identified preoperative to postoperative change in PI as parameters affecting the hip osteoarthritis progression after spinal fusion surgery. Decrease in PI might represent preexisting sacroiliac joint laxity. Patients with this risk factor should be carefully followed for possible hip osteoarthritis progression.

An in-depth analysis of young adults with osteonecrosis secondary to developmental dysplasia of the hip who underwent total hip arthroplasty.

BACKGROUND: Patients with osteonecrosis of the femoral head secondary to DDH frequently require total hip arthroplasty (THA), but it is not well understood which factors necessitate this requirement. We determined the incidence of THA in patients who have osteonecrosis secondary to DDH and factors associated with need for THA. METHODS: We included patients who received closed or open reductions between 1995 and 2005 with subsequent development of osteonecrosis. We determined osteonecrosis according to Bucholz and Ogden; osteoarthritis severity (Kellgren-Lawrence), subluxation (Shenton's line); neck-shaft angle; and acetabular dysplasia (centre-edge and Sharp angles). We also recorded the number of operations of the hip in childhood and reviewed case notes of patients who received THA to describe clinical findings prior to THA. We assessed the association between radiographic variables and the need for THA using univariate logistic regression. RESULTS: Of 140 patients (169 hips), 22 patients received 24 THA (14%) at a mean age of 21.3 ± 3.7 years. Associated with the need for THA were grade III osteonecrosis (OR 4.25; 95% CI 1.70-10.77; p = 0.0019), grade IV osteoarthritis (21.8; 7.55-68.11; p < 0.0001) and subluxation (8.22; 2.91-29.53; p = 0.0003). All patients who required THA reported at least 2 of: severe pain including at night, stiffness, and reduced mobility. Acetabular dysplasia and number of previous operations were not associated with the need for THA. CONCLUSIONS: We identified a 14% incidence of THA by age 34 years in patients with osteonecrosis secondary to DDH. Grade III osteonecrosis (global involvement femoral head and neck) was strongly associated with THA, emphasising the importance to avoid osteonecrosis when treating DDH.

Coxa valga and antetorta configuration leads to underestimation of the femoral component size: a matched case-control study of patients undergoing cementless total hip arthroplasty.

BACKGROUND: Total hip arthroplasty (THA) is the gold standard procedure for patients with end-stage osteoarthritis after failed conservative therapy. Digital templating is commonly employed in preoperative preparation for THA and contributes positively to its outcome. However, the impact of coxa valga and antetorta (CVA) configurations on stem size prediction accuracy remains not reported. Previous studies demonstrated that the size of the lesser trochanter (LT) can be used to determine femoral anteversion on pelvis radiographs. This study investigates the accuracy of preoperative digital templating in predicting stem size in patients with CVA undergoing cementless THA. METHODS: Preoperative radiographs of 620 patients undergoing cementless THA were retrospectively investigated. Radiographs were standardized with patients standing and the leg internally rotated by 15°. A CVA group was established including patients with a CCD angle greater than 140° and a lesser trochanter (LT) size of at least 10 mm for men and 8 mm for women. For the control group, radiographs with a CCD angle ranging from 125-135° and LT size 3-10 mm for men and 3-8 mm for women were selected. Preoperative templating was performed using mediCAD. To reduce confounding factors, case-control matching was carried out for BMI and body height. RESULTS: After case-control matching, a total of thirty-one matches were analyzed. Stem size was underestimated in 74% (23/31) in the CVA and 13% (4/31) in the control group (p < 0.001). Moreover, patients with CVA were more likely to be underestimated by two sizes compared to controls (p < 0.004). In contrast, the exact stem size was predicted more frequently in the control group (p < 0.001). CONCLUSION: Stem size in patients with a CVA configuration are at high risk of being underestimated when using digital templating. These findings can be valuable for guiding in intraoperative decisions and lowering the risk of complications associated with an undersized femoral component.

Surgical Management of Hip-Spine Syndrome: A Systematic Review of the Literature.

BACKGROUND: Hip-spine syndrome (HSS) was first described in 1983 to describe the symptomatology resulting from concomitant lumbar degenerative stenosis and hip osteoarthritis. Numerous studies have sought to understand the underlying pathology and appropriate management of this syndrome. The purpose of this article is to review the literature for the specific imaging characteristics and the optimal surgical treatment of HSS. METHODS: A systematic review was conducted via an electronic database search through PubMed to identify all publications related to HSS. All publications that contained data on patients who underwent surgical treatment for HSS and reported patient-reported outcome measures or radiographic data were included. Exclusion criteria consisted of publications in a language other than English, review articles, and technique articles. RESULTS: Fifteen articles that focused on the surgical management of HSS were identified. Of these 15 articles, 8 reported radiographic outcomes, with most reporting no significant change in spinopelvic parameters before and after surgery. Thirteen articles reported clinical outcomes, with 8 of those 13 articles identifying patient-reported outcome measures to be significantly improved following surgery. CONCLUSIONS: The data on the surgical management of HSS remains sparse. While there is some evidence that total hip arthroplasty in patients who previously underwent spinal fusion may have higher complication rates, there remains debate regarding which surgical problem to address first, the hip or the spine.

Advances in imaging for pre-surgical planning in hip resurfacing arthroplasty.

BACKGROUND: Accurate preoperative templating is essential for the success of hip resurfacing arthroplasty (HRA). While digital radiograph is currently considered the gold standard, stereoradiograph and CT converted 3D methods have shown promising results. However, there is no consensus in the literature regarding the preferred modality for HRA templating, and angular measurements are often overlooked. Thus, this study aimed to: (1) compare the performances of different modality in implant sizing and angle measurements, (2) evaluate the measurement reproducibility, (3) assess the impact of severe osteoarthritis on femoral head sizing, and (4) based on the analysis above, explore the optimal imaging and planning strategy for HRA. HYPOTHESIS: An optimal imaging modality exists for HRA planning regarding implant sizing and angular measurements. MATERIALS AND METHODS: Preoperative imaging data from seventy-seven HRA surgeries were collected. Three raters performed templating using digital radiograph, stereoradiograph, and CT converted 3D models. Measurements for femoral head size, neck-shaft angle, and calcar-shaft angle were obtained. The femoral head sizing was compared to the intraoperative clinical decision. The reproducibility of measurements was assessed using the intraclass correlation coefficient (ICC). Correlations were examined between sizing disagreement and osteoarthritis grade (Tonnis Classification). RESULTS: Digital radiograph, stereoradiograph, and 3D techniques predicted one size off target in 27/77 (35%), 49/70 (70%), and 75/77 (97%) of cases, respectively, corresponding to 1.8±1.6 (0 to 5.67), 0.9±0.7 (0 to 2.67), and 0.4±0.4 (0 to 1.67) sizes off target, indicating statistically significant differences among all three modalities, with p-values all below 0.01. There were no statistically significant differences among the different modalities for angular measurements. Measurements showed moderate to excellent reproducibility (ICC=0.628-0.955). High-grade osteoarthritis did not impact image sizing in any modality (r=0.08-0.22, all p>0.05). DISCUSSION: CT converted 3D models were more accurate for implant sizing in HRA, but did not significantly outperform other modalities in angular measurements. Given the high costs and increased radiation exposure associated with CT, the study recommended using CT scans selectively, particularly for precise femoral head sizing, while alternative imaging methods can be effectively used for angular measurements. LEVEL OF EVIDENCE: III; retrospective comparative diagnostic study.

Should We Wait for Bone-on-Bone Arthritis? Equivalent Clinical Outcomes in Patients Requiring Advanced Imaging Before Primary Total Hip Arthroplasty.

BACKGROUND: Plain radiographs remain the standard for diagnosing osteoarthritis (OA). Total hip arthroplasty (THA) is generally offered only for advanced OA by plain radiographs. Advanced imaging is used as an adjunct to assess OA severity in cases of progressive symptoms with less advanced OA by plain radiographs. The objective of this study was to compare outcomes following THA in patients who have advanced OA visualized by plain radiographs to patients who have less severe OA visualized by plain radiographs. METHODS: From February 2016 to February 2020, 93 patients who had Kellgren-Lawrence (KL) grade 0 to 2 OA and underwent THA were identified. The median age was 65 years, and 55% were women. They were matched 1:3 to patients who underwent THA for KL 4 OA based on age, sex, body mass index, and Charlson Comorbidity Index. The primary outcome was achievement of the Hip Injury and Osteoarthritis Outcome Score for Joint Replacement (HOOS JR) minimum clinically important difference, substantial clinical benefit, and patient-acceptable symptom state at 1 year postoperatively. RESULTS: There was no difference between the KL 0 to 2 and KL 4 cohorts in the achievement of HOOS JR minimum clinically important difference (86 versus 85.6%, P = .922), substantial clinical benefit (81.7 versus 80.2%, P = .751), or patient-acceptable symptom state (89.2 versus 85.6%, P = .374). The KL 0 to 2 cohort had a similar improvement in their 2-year HOOS JR (42.5 versus 38.6, P = .019). CONCLUSIONS: In this series, there was no difference in outcomes following primary THA between patients who have severe OA on plain radiographs (KL 4) compared to those who have less severe OA (KL 0 to 2). In the setting of severe symptoms and the absence of advanced OA on radiographs, advanced imaging can be used to guide treatment and select patients who could benefit from THA.

Two-Dimensional Versus Three-Dimensional Preoperative Planning in Total Hip Arthroplasty.

BACKGROUND: Preoperative planning in total hip arthroplasty (THA) involves utilizing radiographs or advanced imaging modalities, including computerized tomography scans, for precise prediction of implant sizing and positioning. This study aimed to compare 3-dimensional (3D) versus 2-dimensional (2D) preoperative planning in primary THA with respect to key surgical metrics, including restoration of the horizontal and vertical center of rotation (COR), combined offset, and leg length. METHODS: This study included 60 patients undergoing primary THA for symptomatic hip osteoarthritis (OA), randomly allocated to either robotic arm-assisted or conventional THA. Digital 2D templating and 3D planning using the robotic software were performed for all patients. All measurements to evaluate the accuracy of templating methods were conducted on the preoperative computerized tomography scanogram, using the contralateral hip as a reference. Sensitivity analyses explored differences between 2D and 3D planning in patients who had superolateral or medial OA patterns. RESULTS: Compared to 2D templating, 3D templating was associated with less medialization of the horizontal COR (-1.2 versus -0.2 mm, P = .002) and more accurate restoration of the vertical COR (1.63 versus 0.3 mm, P < .001) with respect to the contralateral side. Furthermore, 3D templating was superior for planned restoration of leg length (+0.23 versus -0.74 mm, P = .019). Sensitivity analyses demonstrated that in patients who had medial OA, 3D planning resulted in less medialization of horizontal COR and less offset reduction. Conversely, in patients who had superolateral OA, there was less lateralization of horizontal COR and less offset increase using 3D planning. Additionally, 3D planning showed superior reproducibility for stem, acetabular cup sizes, and neck angle, while 2D planning often led to smaller stem and cup sizes. CONCLUSIONS: Our findings indicated higher accuracy in the planned restoration of native joint mechanics using 3D planning. Additionally, this study highlights distinct variances between the 2 planning methods across different OA pattern subtypes, offering valuable insights for clinicians employing 2D planning.

Automated evaluation of hip abductor muscle quality and size in hip osteoarthritis: Localized muscle regions are strongly associated with overall muscle quality.

Limited information exists regarding abductor muscle quality variation across its length and which locations are most representative of overall muscle quality. This is exacerbated by time-intensive processes for manual muscle segmentation, which limits feasibility of large cohort analyses. The purpose of this study was to develop an automated and localized analysis pipeline that accurately estimates hip abductor muscle quality and size in individuals with mild-to-moderate hip osteoarthritis (OA) and identifies regions of each muscle which provide best estimates of overall muscle quality. Forty-four participants (age 52.7 ± 16.1 years, BMI 23.7 ± 3.4 kg/m2, 14 males) with and without mild-to-moderate radiographic hip OA were recruited for this study. Unilateral hip magnetic resonance (MR) images were acquired on a 3.0 T MR scanner and included axial T1-weighted fast spin echo and 3D axial Iterative Decomposition of water and fat with Echo Asymmetry and Least-squares estimation (IDEAL-IQ) spoiled gradient-recalled echo (SPGR) with multi-peak fat spectrum modeling and single T2* correction. A three dimensional (3D) V-Net convolutional neural network was trained to automatically segment the gluteus medius (GMED), gluteus minimus (GMIN), and tensor fascia lata (TFL) on axial IDEAL-IQ. Agreement between manual and automatic segmentation and associations between axial fat fraction (FF) estimated from IDEAL-IQ and overall muscle FF were evaluated. Dice scores for automatic segmentation were 0.94, 0.87, and 0.91 for GMED, GMIN, and TFL, respectively. GMED, GMIN, and TFL volumetric and FF measures were strongly correlated (r: 0.92-0.99) between automatic and manual segmentations, where all values fell within the 95% limits of agreement of [-9.79 cm3, 17.43 cm3] and [-1.99%, 2.89%], respectively. Axial FF was significantly associated with overall FF with the strongest correlations at 50%, 50%, and 65% the length of the GMED, GMIN, and TFL muscles, respectively (r: 0.93-0.97). An automated and localized analysis can provide efficient and accurate estimates of hip abductor muscle quality and size across muscle length. Specific regions of the muscle may be used to estimate overall muscle quality in an abbreviated evaluation of muscle quality.

Advanced osteoarthritis of the hip as reason for extensive asymmetric leg edema: a rare case report and review of the literature.

An enlarged iliopectineal bursa (IB) can cause pressure on iliofemoral veins. Clinical presentation can manifest as asymmetrical lower extremity edema. This case report demonstrates extensive asymmetrical leg edema caused by femoral vein compression based on iliopectineal bursitis (IB-itis) associated with advanced osteoarthritis (OA) of the left hip joint with an outline of relevant current literature. A female patient presented with left hip pain and edema in the leg. X-ray showed severe OA of the left hip. Computed Tomography (CT) concluded a cystic abnormality at the left iliopsoas muscle associated with the joint consistent with IB-itis, associated with a degenerative left hip joint. Hybrid total hip replacement was performed. At three-month follow-up her left leg showed no longer signs of extensive edema and she walked without the use of walking aids. IB-itis is mostly associated with rheumatoid arthritis (RA). There are no reports which only describe OA as cause of IB-itis. Extensive asymmetrical leg edema can be caused by venous compression of the femoral vein by an IB-itis. If the latter is the consequence of advanced hip OA, a total hip replacement can yield excellent clinical outcomes both functionally and with regard to the edema.

Cohort profile: Worldwide Collaboration on OsteoArthritis prediCtion for the Hip (World COACH) - an international consortium of prospective cohort studies with individual participant data on hip osteoarthritis.

PURPOSE: Hip osteoarthritis (OA) is a major cause of pain and disability worldwide. Lack of effective therapies may reflect poor knowledge on its aetiology and risk factors, and result in the management of end-stage hip OA with costly joint replacement. The Worldwide Collaboration on OsteoArthritis prediCtion for the Hip (World COACH) consortium was established to pool and harmonise individual participant data from prospective cohort studies. The consortium aims to better understand determinants and risk factors for the development and progression of hip OA, to optimise and automate methods for (imaging) analysis, and to develop a personalised prediction model for hip OA. PARTICIPANTS: World COACH aimed to include participants of prospective cohort studies with ≥200 participants, that have hip imaging data available from at least 2 time points at least 4 years apart. All individual participant data, including clinical data, imaging (data), biochemical markers, questionnaires and genetic data, were collected and pooled into a single, individual-level database. FINDINGS TO DATE: World COACH currently consists of 9 cohorts, with 38 021 participants aged 18-80 years at baseline. Overall, 71% of the participants were women and mean baseline age was 65.3±8.6 years. Over 34 000 participants had baseline pelvic radiographs available, and over 22 000 had an additional pelvic radiograph after 8-12 years of follow-up. Even longer radiographic follow-up (15-25 years) is available for over 6000 of these participants. FUTURE PLANS: The World COACH consortium offers unique opportunities for studies on the relationship between determinants/risk factors and the development or progression of hip OA, by using harmonised data on clinical findings, imaging, biomarkers, genetics and lifestyle. This provides a unique opportunity to develop a personalised hip OA risk prediction model and to optimise methods for imaging analysis of the hip.