Accuracy of conventional motion capture in measuring hip joint center location and hip rotations during gait, squat, and step-up activities.

Accurate measurements of hip joint kinematics are essential for improving our understanding of the effects of injury, disease, and surgical intervention on long-term hip joint health. This study assessed the accuracy of conventional motion capture (MoCap) for measuring hip joint center (HJC) location and hip joint angles during gait, squat, and step-up activities while using dynamic biplane radiography (DBR) as the reference standard. Twenty-four young adults performed six trials of treadmill walking, six body-weight squats, and six step-ups within a biplane radiography system. Synchronized biplane radiographs were collected at 50 images per second and MoCap was collected simultaneously at 100 images per second. Bone motion during each activity was determined by matching digitally reconstructed radiographs, created from subject-specific CT-based bone models, to the biplane radiographs using a validated registration process. Errors in estimating HJC location and hip angles using MoCap were quantified by the root mean squared error (RMSE) across all frames of available data. The MoCap error in estimating HJC location was larger during step-up (up to 89.3 mm) than during gait (up to 16.6 mm) or squat (up to 31.4 mm) in all three anatomic directions (all p < 0.001). RMSE in hip joint flexion (7.2°) and abduction (4.3°) during gait was less than during squat (23.8° and 8.9°) and step-up (20.1° and 10.6°) (all p < 0.01). Clinical analysis and computational models that rely on skin-mounted markers to estimate hip kinematics should be interpreted with caution, especially during activities that involve deeper hip flexion.

Comparison of quality and interpretation of newborn ultrasound screening examinations for developmental dysplasia of the hip by basically trained nurses and junior physicians with no previous ultrasound experience.

BACKGROUND: We are obliged to give babies the chance to profit from a nationwide screening of developmental dysplasia of the hip in very rural areas of Mongolia, where trained physicians are scarce. This study aimed to compare the quality and interpretation of hip ultrasound screening examinations performed by nurses and junior physicians. METHODS: A group of 6 nurses and 6 junior physician volunteers with no previous ultrasound experience underwent Graf's standard training in hands-on practice. Newborns were examined before discharge from the hospital, according to the national guideline. Two standard documentation images of each hip were saved digitally. The groups were compared on the proportion of good quality of sonograms and correct interpretation. Two Swiss supervisors' agreed diagnosis according to Graf was considered the final reference for the study purposes. RESULTS: A total of 201 newborns (402 hips or 804 sonograms) were examined in the study, with a mean age of 1.3±0.8 days at examination. Junior physicians examined 100 newborns (200 hips or 400 sonograms), while nurses examined 101 newborns (202 hips or 404 sonograms). The study subjects of the two groups were well balanced for the distribution of baseline characteristics. The study observed no statistically significant difference in the quality of Graf's standard plane images between the providers. Eventually, 92.0% (92) of the physician group and 89.1% (90) of the nurse group were correctly diagnosed as "Group A" (Graf's Type 1 hip) or "Non-Group A" hips (p = 0.484). The most common errors among the groups were a missing lower limb, wrong measurement lines, and technical problems. CONCLUSION: Our study provides evidence that while there might be a trend of slightly more technical mistakes in the nurse group, the overall diagnosis accuracy is similar to junior physicians after receiving standard training in Graf's hip ultrasound method. However, after basic training, regular quality control is a must and all participants should receive refresher trainings. More specifically, nurses need training in the identification of anatomical structures.

Sex-based differences in neck selectivity in total hip arthroplasty using a modular femoral neck system.

BACKGROUND: Dislocation is a major complication of total hip arthroplasty (THA). The modular femoral neck system provides practical advantages by allowing adjustment of neck version and length in the presence of intraoperative instability. Anatomical studies have identified morphological differences in the hip joint between men and women. Despite sex-based differences in hip morphology, it remains unclear whether such differences affect neck selectivity in THA using a modular neck system and whether this approach achieves anatomical reconstruction, thereby reducing complications such as dislocation. This study aimed to investigate gender differences in neck selectivity in THA with the modular neck system and assess the clinical impact of the modular neck system. METHODS: A total of 163 THAs using a modular neck system were included in this study. Data on the type of modular neck and intraoperative range of motion (ROM) were retrieved from patient records. Pre- and post-operative leg length differences (LLD) were examined as part of the radiographic assessment. Dislocation was investigated as a postoperative complication. RESULTS: Neck selectivity did not significantly differ between men and women. The comparison of pre- and post-operative LLD revealed a tendency for varus necks to improve LLD more than version-controlled necks. Furthermore, no significant correlation was found between intraoperative ROM and neck selectivity, or postoperative dislocation and neck selectivity. CONCLUSIONS: This study on THA with a modular neck system provided valuable insights into sex-based differences in neck selectivity and highlighted the potential benefits of the modular neck system in addressing LLD and preventing postoperative dislocation.

Computer-Assisted Arthroscopic Cam Resection.

Determining the appropriate femoral cam resection during hip arthroscopy for femoroacetabular impingement syndrome is both critical for the patient and challenging for the surgeon. Incomplete bone resection is a leading cause of failed hip arthroscopy, whereas over-resection may increase the risk of femoral neck fracture. The alpha angle is a validated 2-dimensional radiographic measurement used to both diagnose femoroacetabular impingement syndrome preoperatively and to determine resection adequacy postoperatively. Computer-assisted intraoperative guidance systems enhance the accuracy of femoral cam resection, although a preoperative 3-dimensional computed tomography scan may be required. Other systems, such as the HipCheck software (Stryker, Kalamazoo, MI), have been developed to provide intraoperative guidance with live feedback using simultaneous alpha angle measurements overlayed on fluoroscopic images without the requirement for routine preoperative computed tomography. Via intraoperative touchscreen navigation, the surgeon identifies the midpoint of the femoral neck and femoral head. A commercial software program provides real-time alpha angle measurements, as well as enhanced visualization of the femoral cam deformity with an adjustable resection curve. Before the surgeon performs the cam resection, the software provides a template for appropriate resection depth in 6 positions of the hip. Upon completion of the femoral cam resection, the hip is again assessed in the same 6 positions and the alpha angle is assessed to ensure a complete resection.

Neonatal Ultrasound and Radiographic Markers of Hip Dysplasia in Young Adults.

OBJECTIVES: To examine radiologic outcomes at skeletal maturity of sonographically normal, immature, mildly, and severely dysplastic newborn hips. METHODS: During 1988 to 1990, 11 925 newborns were enrolled in a randomized controlled trial examining screening strategies for developmental hip dysplasia. In total, 4469 were invited to clinical and radiologic follow-up 18 years later, of which 1735 had received neonatal ultrasound. Radiographic markers for dysplasia in left adult hips included the center-edge (CE) angle. RESULTS: At follow-up, 984 of 1735 (56.7%) with newborn ultrasound met, of which 966 (614 females) had valid radiographs and were thus included. For females, 34 (10.2%) and 1 (0.3%) of the 332 sonographically normal left neonatal hips were judged borderline (20°≤ CE <25°) or dysplastic (CE <20°) at skeletal maturity respectively. Corresponding numbers were 36 (19.7%) and 3 (1.6%) of the 183 immature, 12 (15.6%) and 2 (2.6%) of the 77 mildly dysplastic, and 3 (13.6%) and 3 (13.6%) of the 22 severely dysplastic neonatal left hips (P ≤ .001). In males, no associations were found. In females, adult joint hypermobility was associated with sonographic neonatal hip instability (P = .046), as well as with adult acetabular dysplasia (P = .024). CONCLUSIONS: Significant associations between neonatal hip phenotypes and adult dysplasia were revealed in females. This indicates the possibility of different mechanisms affecting the course of developmental dysplasia of the hip for females and males, prompting consideration of prolonged clinical and radiologic follow-up for females with dysplastic neonatal hips. Results in males are limited by low numbers of dysplastic hips. The significance of joint hypermobility warrants further investigation.

Modern Hip Arthroscopy for FAIS May Delay the Natural History of Osteoarthritis in 25% of Patients: A 12-Year Follow-up Analysis.

BACKGROUND: Little is known about the effect of modern hip arthroscopy on the natural history of femoroacetabular impingement syndrome (FAIS) with respect to joint preservation. PURPOSE: To (1) characterize the natural history of FAIS and (2) understand the effect of modern hip arthroscopy by radiographically comparing the hips of patients who underwent only unilateral primary hip arthroscopy with a minimum follow-up of 10 years. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Between 2010 and 2012, 619 consecutive patients were reviewed from the practice of a single fellowship-trained hip arthroscopic surgeon. Inclusion criteria were FAIS, bilateral radiographic findings of femoroacetabular impingement, primary unilateral hip arthroscopy (labral repair, femoroplasty, or capsular closure), and minimum 10-year follow-up. The preoperative and minimum 10-year postoperative radiographs of patients were evaluated at each time point. Both operative and nonoperative hips were graded using the Tönnis classification or the presence of hip arthroplasty by 2 independent reviewers. Subgroup analyses were performed. RESULTS: A total of 200 hips from 100 patients were evaluated at a mean follow-up of 12.0 years. Preoperatively, 98% and 99% of operative and nonoperative hips were evaluated as Tönnis grades 0 and 1, respectively; 5% of nonoperative hips had worse Tönnis grades than operative hips. The nonoperative hip advanced to a worse Tönnis grade in 48% (48/100) of cases compared with 28% (28/100) among operative hips. At follow-up, Tönnis grades between hips were equal in 70% (70/100) of the cases, the operative hip had a better grade 25% (25/100) of the time, and the nonoperative hip had a better grade 5% (5/100) of the time. Modern hip arthroscopy was associated with a relative risk reduction of 42% in osteoarthritis progression. Impingement with borderline dysplasia, age, preoperative Tönnis grade, and alpha angle >65° were key risk factors in the radiographic progression of osteoarthritis. CONCLUSION: Although the majority of patients (70%) undergoing hip arthroscopy for FAIS did not experience differences between operative and nonoperative hips in terms of the radiographic progression of osteoarthritis, the natural history may be favorably altered for 25% of patients whose Tönnis grade was better after undergoing arthroscopic correction. Modern hip arthroscopy indications and techniques represent a valid joint-preservation procedure conferring a relative risk reduction of 42% in the progression of osteoarthritis. Arthroscopy for mixed patterns of impingement and instability were the fastest to degenerate.

Acetabular "Fleck" Sign: Outcomes of Surgical Repair.

BACKGROUND: Traumatic, posterior hip dislocations in the pediatric population are typically managed by closed reduction to achieve a concentric hip joint. The presence of an acetabular "fleck" sign, despite concentric reduction, has been shown to signify significant hip pathology. The purpose of this study was to evaluate the outcomes of open labral repair through a surgical hip dislocation (SHD) in a consecutive series of patients with an acetabular "fleck" sign associated with a traumatic hip dislocation/subluxation. METHODS: A retrospective review of patients between 2008 and 2022 who presented to a single, level 1 pediatric trauma center with a traumatic posterior hip dislocation/subluxation was performed. Patients were included if they had an acetabular "fleck" sign on advanced imaging and underwent open labral repair through SHD. Medical records were reviewed for sex, age, laterality, mechanism of injury (MOI), and associated orthopaedic injuries. The modified Harris hip score (mHHS) was utilized as the primary clinical outcomes measure. Patients were assessed for the presence of heterotopic ossification (HO) and complications, including implant issues, infection, avascular necrosis (AVN), and post-traumatic dysplasia. RESULTS: Twenty-nine patients (23 male, average age: 13.0±2.7 y; range: 5.2 to 17.3) were identified. Eighteen injuries were sports related, 9 caused by motor vehicle accidents, and 1 pedestrian struck. All patients were found to have an acetabular "fleck" sign on CT (26 patients) or MRI (5 patients). Associated injuries included: femoral head fracture (n=6), pelvic ring injury (n=3), ipsilateral femur fracture (n=2), and ipsilateral PCL avulsion (n=1). At the latest follow-up (2.2±1.4 y), all patients had returned to preinjury activity/sport. Three patients developed asymptomatic, grade 1 HO in the greater trochanter region. There was no incidence of AVN. One patient developed post-traumatic acetabular dysplasia due to early triradiate closure. mHHS scores showed excellent outcomes (n=21, 94.9±7.4, range: 81 to 100.1). CONCLUSIONS: The acetabular "fleck" sign indicates a consistent pattern of osteochondral avulsion of the posterior/superior labrum. Restoring native hip anatomy and stability is likely to improve outcomes. SHD with open labral repair in these patients produces excellent clinical outcomes, with no reported cases of AVN. LEVEL OF EVIDENCE: Level IV-therapeutic.

Efficient hip joint distraction using the AO large femoral distractor in treating acetabular fractures associated with marginal impaction and intraarticular incarcerated fragments.

PURPOSE: The results after acetabular fracture are primarily related to the quality of articular reduction. Using the AO large femoral distractor, incarcerated fragments can be easily removed, and marginally impacted fragments can be elevated under direct visualization without further re-dislocating the joint. The current study aimed to evaluate our early results of using the AO large femoral distractor as an assisting tool during ORIF of acetabular fractures associated with marginal impaction or intraarticular incarcerated fragments. METHODS: Eighteen patients were included in this retrospective case series study diagnosed with an acetabular fracture associated with either marginal impaction injury or an intraarticular incarcerated fragment. On a usual operative table, all patients were operated upon in a prone position through the Kocher Langenbeck approach. The AO large femoral distractor was used to facilitate hip joint distraction. Postoperative fracture reduction and joint clearance were assessed in the immediate postoperative CT scans. RESULTS: The average age of the patients was 30 ± 8.2 years; 13 (72.2%) were males. All cases had a posterior wall fracture, and it was associated with transverse fractures, posterior column fractures, and T-type fractures in five (27.8%), two (11.1%), and one (5.6%) patients, respectively. Intraarticular incarcerated fragments were present in 13 (72.2%) cases and marginal impaction in five (27.8%). Fracture reduction measured on the postoperative CT scans showed an anatomical reduction in 14 (77.8%) patients, imperfect in four (22.2%), and complete clearance of the hip joint of any incarcerated fragments. CONCLUSION: The use of the AO large femoral distractor is a reliable and reproducible technique that can be applied to assist in the removal of incarcerated intraarticular fragments and to ease the reduction of marginally impacted injuries associated with acetabular fractures.

Hip Capsulolabral Complex: Anatomy, Disease, MRI Features, and Postoperative Appearance.

The hip is a uniquely constrained joint with critical static stability provided by the labrum, capsule and capsular ligaments, and ligamentum teres. The labrum is a fibrocartilaginous structure along the acetabular rim that encircles most of the femoral head. Labral tears are localized based on the clock-face method, which determines the extent of the tear while providing consistent terminology for reporting. Normal labral variants can mimic labral disease and can be differentiated by assessment of thickness or width, shape, borders, location, and associated abnormalities. The Lage and Czerny classification systems are currently the most well-known arthroscopic and imaging systems, respectively. Femoroacetabular impingement is a risk factor for development of labral tears and is classified according to bone dysmorphisms of the femur ("cam") or acetabulum ("pincer") or combinations of both (mixed). The capsule consists of longitudinal fibers reinforced by ligaments (iliofemoral, pubofemoral, ischiofemoral) and circular fibers. Capsular injuries occur secondary to hip dislocation or iatrogenically after capsulotomy. Capsular repair improves hip stability at the expense of capsular overtightening and inadvertent chondral injury. The ligamentum teres is situated between the acetabular notch and the fovea of the femoral head. Initially considered to be inconsequential, recent studies have recognized its role in hip rotational stability. Existing classification systems of ligamentum teres tears account for injury mechanism, arthroscopic findings, and treatment options. Injuries to the labrum, capsule, and ligamentum teres are implicated in symptoms of hip instability. The authors discuss the labrum, capsule, and ligamentum teres, highlighting their anatomy, pathologic conditions, MRI features, and postoperative appearance. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Incorporating patient-specific hip orientation from weightbearing computed tomography affects discrete element analysis-computed regional joint contact mechanics in individuals treated with periacetabular osteotomy for hip dysplasia.

Computational models of the hip often omit patient-specific functional orientation when placing imaging-derived bony geometry into anatomic landmark-based coordinate systems for application of joint loading schemes. The purpose of this study was to determine if this omission meaningfully alters computed contact mechanics. Discrete element analysis models were created from non-weightbearing (NWB) clinical CT scans of 10 hip dysplasia patients (11 hips) and oriented in the International Society of Biomechanics (ISB) coordinate system (NWB-ISB). Three additional models were generated for each hip by adding patient-specific stance information obtained via weightbearing CT (WBCT) to each ISB-oriented model: (1) patient-specific sagittal tilt added (WBCT-sagittal), (2) coronal and axial rotation from optical motion capture added to (1; WBCT-combo), and (3) WBCT-derived axial, sagittal, and coronal rotation added to (1; WBCT-original). Identical gait cycle loading was applied to all models for a given hip, and computed contact stress and contact area were compared between model initialization techniques. Addition of sagittal tilt did not significantly change whole-joint peak (p = 0.922) or mean (p = 0.871) contact stress or contact area (p = 0.638). Inclusion of motion-captured coronal and axial rotation (WBCT-combo) decreased peak contact stress (p = 0.014) and slightly increased average contact area (p = 0.071) from WBCT-sagittal models. Including all WBCT-derived rotations (WBCT-original) further reduced computed peak contact stress (p = 0.001) and significantly increased contact area (p = 0.001). Variably significant differences (p = 0.001-1.0) in patient-specific acetabular subregion mechanics indicate the importance of functional orientation incorporation for modeling applications in which local contact mechanics are of interest.

Editorial Commentary: Borderline Hip Dysplasia Combined With Increased Anteversion and Ligamentum Teres Disruption Is a Recipe for Hip Microinstability.

The ligamentum teres (LT) is known to play a role as a secondary stabilizer of the hip joint. LT tears can be associated with hip instability. In patients with borderline developmental dysplasia of the hip (BDDH), the correlation between LT tears and microinstability is even more pronounced because of the increased mechanical stress placed on the ligament. This relationship may lead certain surgeons to consider new indications for LT reconstructions. However, caution is warranted regarding the potential role of LT reconstruction in these patients, particularly since the primary deficiency in BDDH is bony undercoverage. Addressing this bony undercoverage should be a primary consideration that may be supplemented with other procedures, which may include addressing soft-tissue injuries around the hip such as LT tears. This is especially the case in those patients with persistent symptoms after management of labral tears or LT disruption.

Editorial Commentary: Small Labral Size on Magnetic Resonance Imaging Is an Indication for Labral Reconstruction in the Setting of Revision Hip Arthroscopy.

Revision hip arthroscopy is an increasingly common procedure as rates of primary hip arthroscopy rise. Etiologies for symptom recurrence may include residual femoroacetabular impingement, cam over-resection, labral pathology, chondral wear, adhesions, and instability. This has spawned sophisticated surgical techniques in hip arthroscopy including labral reconstruction. Indications for labral reconstruction in the revision setting obviously include labral deficiency. In addition, in the absence of other obvious reasons for failure of the primary procedure, a labral reconstruction should be considered for diminutive labra. The ability to predict labral size before surgery based on magnetic resonance imaging can be invaluable.

Editorial Commentary: Standardized Evaluation of Cartilage Damage and Restoration in Hip Arthroscopy Requires Consideration of Clinical, Imaging, and Patient-Reported Outcomes.

Articular cartilage lesions of the acetabulum may result in significant pain and dysfunction for patients with treatment options consisting of either microfracture or various forms of cartilage restoration procedures. A systematic review of 529 patients demonstrated similar, if not lower, reoperation rates and patient-reported outcomes in patients receiving cartilage restoration procedures compared with microfracture. The primary outcomes examined in this review were reoperation rates and patient-reported outcomes with no clear mention of radiographic outcomes and no clearly defined indications as to who would benefit from a cartilage-based procedure. This raises the question as to whether there should be a consensus-based and standardized criteria established and standardized among the hip preservation expert community to evaluate the success of these cartilage restoration procedures from an imaging standpoint. These criteria can also be incorporated into a composite evaluation that combines clinical, imaging, and patient-reported outcomes to determine optimal patient candidacy for cartilage procedures as well. This would be a very useful steppingstone for much-needed future Level I randomized studies or prospective, registry-based data on this topic.

A New Arthroscopic Classification for Chondrolabral Disease in Patients Undergoing Surgery for Developmental Dysplasia of the Hip.

BACKGROUND: Current classification systems for intra-articular pathology intraoperatively have been described for patients with femoroacetabular impingement rather than dysplasia. PURPOSE: To (1) describe intra-articular findings in dysplastic hips undergoing combined hip arthroscopy and periacetabular osteotomy (PAO); (2) propose a new chondrolabral classification system for dysplastic hips based on these findings; and (3) correlate patient-reported outcome measures (PROM) with the newly proposed classification. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A total of 46 hips underwent combined hip arthroscopy and PAO at our institution between September 2013 and December 2014, irrespective of symptoms or radiographic findings. PROMs were evaluated preoperatively and at 2 years postoperatively. At the time of hip arthroscopy, the chondrolabral junction was classified as normal without tear (1 hip, type 1); hypertrophic labrum without chondrolabral disruption (19 hips, type 2); chondrolabral disruption on the articular side, not extending into the capsular side (16 hips, type 3A); chondrolabral disruption extending through the capsular side (3 hips, type 3B); and exposed acetabular subchondral bone (7 hips, type 4). RESULTS: There was a significant difference in postoperative modified Harris Hip Score (mHHS) (P = .020), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain scores (P = .037), and WOMAC total scores (P = .049) between chondrolabral junction types. Post hoc analyses demonstrated significant differences between type 2 (84.9 ± 12.9) and type 3A (67.8 ± 20.7; P = .198), and between type 2 and type 4 (59.3 ± 24.3; P = .011) in postoperative mHHS scores; and between type 2 (83.9 ± 12.9) and type 3A (68.9 ± 23.7; P = .045) in postoperative WOMAC total scores. In multivariate analysis, chondrolabral type 3 or type 4, age >35 years, and previous surgery were significantly correlated with worse mHHS scores at 2 years. CONCLUSION: This new chondrolabral classification is proposed to describe intra-articular pathology seen during combined hip arthroscopy and PAO, specifically in dysplastic hips. More advanced chondrolabral disease was associated with worse PROMs at 2 years.

Comparison of the distraction index and Norberg angle with radiographic grading of canine hip dysplasia.

The Orthopedic Foundation for Animals (OFA) radiographic grading system stands as a well-established benchmark for categorizing hip dysplasia in canines. Although more objective techniques to quantify early hip laxity in young dogs, such as the Norberg angle (NA) and distraction index (DI), have been documented, there is a scarcity of published studies that directly compare these radiographic measures. The primary objectives of this prospective, analytical study were to assess and compare the NA and DI measures with OFA grades within a cohort of dogs. Thirty dogs (57 hip joints) were evaluated, with a mean age of 5.4 ± 2.9 years and a mean body weight of 34.3 ± 7.1 kg. The discriminative power of hip dysplasia for DI and NA used OFA as a reference were compared by multivariate discriminant analysis test. Using the DI (≤0.3) 12 joints were classified as normal, using NA (≥105°) 24 joints and using OFA (≤3) 29. When comparing the discriminant power of NA with OFA resulting similar (P = .8324) with correct classifications of 81% using cross validation, however, the discriminant power of dysplasia of the DI resulted significantly greater (P = .0034) than OFA with correct classifications of only 59% using cross-validation, consequently it was possible determined that of 29 patients with OFA ≤ 3, 20 had DI > 0.3. These findings demonstrated that phenotypic healthy dogs according to OFA grading can present passive hip joint laxity, as demonstrated by radiographic evaluation with distraction. Furthermore, DI can contribute to the screening of CHD when evaluated in conjunction with OFA grading.

[Effectiveness of combined anteversion angle technique in total hip arthroplasty for treatment of ankylosing spondylitis affecting hip joint].

Objective: To explore the effectiveness of the combined anteversion angle technique in total hip arthroplasty (THA) for treating ankylosing spondylitis (AS) affecting the hip joint. Methods: A retrospective analysis was conducted on the clinical data of 73 patients with AS affecting the hip joint who underwent THA between August 2018 and August 2021. According to whether the combined anteversion angle technique was used in THA, the patients were divided into study group (37 cases, combined anteversion angle technique was used in THA) and control group (36 cases, traditional THA). There was no significant difference in baseline data such as gender, age, body mass index, disease duration, preoperative Harris score, range of motion (ROM), acetabular anteversion angle, acetabular abduction angle, femoral anteversion angle, and combined anteversion angle between the two groups ( P>0.05). The operation time, hospital stay, and complications of the two groups were recorded and compared. The Harris score and hip ROM were compared between the two groups before operation, at 1, 3, 6, 12 months after operation, and at last follow-up. The acetabular component anteversion angle, femoral component anteversion angle, acetabular component abduction angle, and component combined anteversion angle were measured postoperatively. Results: The operation time in the study group was significantly shorter than that in the control group ( P<0.05), and there was no significant difference in hospital stay between the two groups ( P>0.05). There was no intraoperative complication such as acetabular and proximal femoral fractures, neurovascular injuries in both groups, and the incisions healed by first intention. All patients were followed up 2-3 years, with an average of 2.4 years; there was no significant difference in the follow-up time between the two groups ( P>0.05). During the follow-up period, there was no complication such as hip dislocation, wound infection, delayed wound healing, deep venous thrombosis, and hip dislocation in both groups. The hip Harris score and ROM of the two groups gradually increased with time after operation, and the differences were significant when compared with those before operation ( P<0.05); the above two indicators of the study group were significantly better than those of the control group at each time point after operation ( P<0.05). Extensive bone ingrowth on the surface of the components could be observed in the anteroposterior X-ray films of the hip joint of the two groups at 12 months after operation, and the acetabular components was stable without femoral stem subsidence, osteolysis around the components, and heterotopic ossification. At last follow-up, the acetabular component anteversion angle, femoral component anteversion angle, and component combined anteversion angle in the study group were significantly superior to those in the control group ( P<0.05), except that there was no significant difference in the acetabular component abduction angle between the two groups ( P>0.05). Conclusion: For patients with AS affecting the hip joint, the use of the combined anteversion angle technique during THA effectively promotes the recovery of hip joint function and enhances the postoperative quality of life of patients when compared to traditional THA.

Successful therapy of complex regional pain syndrome after hip arthroscopy for femoroacetabular impingement syndrome: a case report.

BACKGROUND: Complex regional pain syndrome is a neuropathic pain disorder associated with ongoing pain that persists beyond the usual expected tissue healing time and that is disproportionate to the degree of tissue injury present. Complex regional pain syndrome after hip arthroscopy has not been reported before. Hip arthroscopy is a fast-growing domain that could lead to an increasing number of complex regional pain syndrome cases, probably owing to the high traction forces that are necessary. CASE PRESENTATION: We report the case of a 30-year-old German female semiprofessional tennis player who presented with complex regional pain syndrome type I in the lower leg 3 weeks after hip arthroscopy for femoroacetabular impingement syndrome with suture anchor labral repair and femoroplasty. After 2 months of immediate multimodal conservative therapy including administration of gabapentin, prompt full weight-bearing, and intensified physiotherapy, complete recovery was achieved. CONCLUSION: Complex regional pain syndrome does occur after elective hip arthroscopy. Disproportionate postoperative pain or other symptoms raising suspicion of complex regional pain syndrome should be promptly evaluated and treated through a multimodal approach. Postless hip arthroscopy may be advantageous.

Intermediate-Term Outcomes of Hip Arthroscopy for Femoroacetabular Impingement Syndrome in Patients With Global Versus Isolated Lateral Acetabular Overcoverage.

BACKGROUND: Previous studies evaluating the outcomes of hip arthroscopy for patients with global acetabular overcoverage and focal superolateral acetabular overcoverage suffer from short-term follow-up and inconsistent radiographic criteria when defining these subpopulations of patients with femoroacetabular impingement syndrome (FAIS). PURPOSE: To evaluate the intermediate-term postoperative outcomes for patients with FAIS in the setting of global acetabular overcoverage, lateral acetabular overcoverage, and normal acetabular coverage. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Patients undergoing hip arthroscopy for FAIS were enrolled in a prospective cohort study, and those with a minimum follow-up of 5 years were included in this analysis. Patients were grouped based on type of acetabular coverage: global overcoverage (lateral center-edge angle [LCEA] ≥40°, with coxa profunda), lateral overcoverage (LCEA ≥40°, without coxa profunda), and no overcoverage (LCEA <40°). Functional outcomes (modified Harris Hip Score and Nonarthritic Hip Score) and failure of primary hip arthroscopy were compared between groups. RESULTS: In total, 94 patients (mean age, 41.9 ± 14.2 years) were included with a mean follow-up duration of 6.1 ± 0.9 years. Of these patients, 40.4% had no acetabular overcoverage, 36.2% had lateral overcoverage, and 23.4% had global overcoverage. There was no difference between groups with respect to percentage of patients who underwent reoperation for either revision arthroscopy or conversion to total hip arthroplasty (28.9% for the normal acetabular coverage group, 29.4% for the lateral overcoverage group, and 31.8% for the global overcoverage group; P = .971). Among patients for whom primary hip arthroscopy did not fail, there was no difference in 5-year functional outcomes between groups. Postoperative LCEA >40° (ß = -13.3; 95% CI, -24.1 to -2.6; P = .016), female sex (ß = -14.5; 95% CI, -22.7 to -6.2; P = .001), and higher body mass index (ß = -1.9; 95% CI, -2.8 to -1.0; P < .001) were associated with worse intermediate-term hip function in terms of modified Harris Hip Score. CONCLUSION: There was no difference in functional outcomes or rate of reoperation at a minimum of 5 years postoperatively between those with global acetabular overcoverage, those with regional lateral overcoverage, and those with normal acetabular coverage. Provided that an appropriate acetabuloplasty is performed, there is no evidence to suggest that global acetabular overcoverage portends a worse prognosis than other FAIS subtypes.

Femoral Anteversion Is Associated With a Thinner Anterior Capsule in Patients With Femoroacetabular Impingement Syndrome.

PURPOSE: To measure femoral torsion on computed tomography images in patients with femoroacetabular impingement syndrome and explore whether femoral torsion was significantly correlated with anterior capsular thickness. METHODS: Prospectively collected data of surgical patients were retrospectively reviewed. Only patients aged 16 to 55 years who underwent primary hip surgery were included in this study. Patients with a history of revision hip surgery, previous knee surgery, hip dysplasia, hip synovitis, and/or incomplete radiographs and medical records were excluded from the study. Femoral torsion was measured via computed tomography imaging using transcondylar slices of the knee. Anterior capsular thickness was measured using oblique-sagittal sequences on a 3.0-T magnetic resonance imaging system. The association between anterior capsular thickness and related variables, including femoral torsion, was assessed via multiple linear regression. The patients were then divided into 2 groups to further confirm the effect of femoral torsion on capsular thickness: Patients in the study group had hips with moderate (20°-25°) or severe (>25°) antetorsion, whereas patients in the control group had hips with normal torsion (5°-20°) or retrotorsion (<5°). Anterior capsular thickness was also compared between the 2 groups. RESULTS: A total of 156 patients (89 female patients [57.1%] and 67 male patients [42.9%]) were finally included in the study. The mean age and body mass index of the included patients were 35.8 ± 11.2 years and 22.7 ± 3.5, respectively. The mean femoral torsion for the entire study population was 15.9° ± 8.9°. Multivariable regression analysis showed that femoral torsion (P < .001) and sex (P = .002) were significantly correlated with anterior capsular thickness. Propensity-score matching yielded 50 hips in the study group and 50 hips in the control group on femoral torsion subanalysis. The results showed that anterior capsular thickness was significantly smaller in the study group than in the control group (3.8 ± 0.5 mm vs 4.7 ± 0.7 mm, P < .001). CONCLUSIONS: Femoral torsion is significantly inversely correlated with anterior capsular thickness. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Is there a reduction in hip destruction under a treat-to-target strategy in patients with rheumatoid arthritis?

OBJECTIVES: The treatments for rheumatoid arthritis (RA) have been greatly improved, and the tight control of disease activity yields superior clinical outcomes. This study aimed to elucidate the accompanying changes in hip destruction following the implementation of a treat-to-target strategy for patients with RA. METHODS: We extracted 190 hips over two periods, i.e. the early period (1998-2003) and the late period (2013-19), with 103 and 87 hips, respectively. The observed rheumatic changes, such as inward migration, upward migration, and femoral head collapse, were quantitatively evaluated, while osteoarthritic changes, such as the formation of a capital drop, were investigated from radiographs before primary total hip arthroplasty. RESULTS: A comparison of the two periods' data showed that the degree of inward migration (-3.44 vs. -7.45 mm; P < .001) and upward migration (+4.3 vs. +0.95 mm; P < .001) significantly decreased in the late-period group. The collapse of the femoral head was not significantly different. The incidence of capital drops was significantly higher in the late-period group (7.8% vs. 27.5%; P < .001). CONCLUSIONS: The degree of inward and upward migration representative of rheumatic changes reduced, whereas the frequency of capital drops as osteoarthritic changes increased during the late period.