Acetabular Socket Research Articles

A comparative study of four combined methods for planning access to the anterior acetabular column for nail placement

To investigate global optimisation of anterior acetabular column pinning channels can be achieved based on large density point cloud data. Data were collected on the CT scans of the normal pelvis in 40 adults from January 2022 to January 2023, including 22 males and 18 females, aged 20 to 54 years old. Medical imaging data from three of the samples were selected for experimental study. In planning access for anterior acetabular column pinning, to address the issue of whether the current CAD planning methods were advanced or not, four combinations of the same point cloud acquisition channels, different directional line creation software, and the same 3D design and virtual experiment software were proposed: Mimics+Imageware+UG, Mimics+3DReshaper+UG, Mimics+ZEISS Quality Suite+UG and Mimics+Design X+UG, and directional lines created based on the centroid point set and solid point cloud of the secondary pruning model, respectively, and it applied to the planning of the left anterior column pinning channel of the three acetabular samples. The maximum internally connected cylinder without acetabular socket and pubic bone penetration was used as a safe passage for nailing of the anterior acetabular column to evaluate the advancement of each method. The fitting effect of the directional line was better than that of the unnoised solid point cloud when the central point set with obvious relevant features was selected as the sample points;and the combination of Mimics+Imageware+UG and Mimics+3DReshaper+UG could efficiently and stably obtain the desirable planning results when planning with the central point set, respectively, in the three acetabular samples 1, 2, 3. The maximum internal joint circle diameters obtained in samples 1, 2, and 3 were 10.35 mm, 9.62 mm, and 9.24 mm;and when the directional lines were based on the solid point cloud the combined methods of Mimics+ZEISS Quality Suite+UG and Mimics+Design X+UG were not applicable;whereas the Mimics+3DReshaper+UG the solid point cloud denoising planning method could stably obtain the maximum value of the safe channel for nail placement, and the maximum internal joint circle diameters obtained in acetabular samples 1, 2, and 3 are 10.66 mm, 10.96 mm, and 9.48 mm, respectively. It is recommended that the nail placement channel planners use robust Mimics+Imageware+UG or Mimics+3DReshaper+UG centre point set planning method, and if there is enough time, it is recommended to use the solid point cloud denoising planning method of Mimics+3DReshaper+UG in order to obtain the maximum value of safe channels for nail placement.

Poster 222: Long-term Survivorship in Patients with Coxa Profunda and Acetabular Overcoverage: An Average 11-Year Follow-up After Hip Arthroscopy

Objectives: A prior study investigating 2-year patient-reported outcomes (PROs) following hip arthroscopy found that patients with coxa profunda and acetabular overcoverage report worse improvements yet similar overall outcomes scores. Regarding conversion to total hip arthroplasty (THA), however, patients with coxa profunda and overcoverage experienced significantly lower rates of survivorship (88.9% vs 100%; p = 0.04). When considering long-term outcomes, a recent study by Domb et al. found an 85.7% 10-year survivorship in patients after hip arthroscopy. Currently, there remains a paucity of literature on the effects of a deep acetabular socket and pincer-type femoroacetabular impingement on patient outcomes beyond 2-years follow-up. The objective of the present study was to report the long-term survivorship, revision surgery rate, patient satisfaction, pain level, and functional outcome scores in patients with coxa profunda and acetabular overcoverage following hip arthroscopy. Methods: This was an institutional review board-approved retrospective cohort study of patients with coxa profunda and a LCE angle > 40° who underwent hip arthroscopy for labral tears or FAI between November 2002 and May 2013. After failing conservative management, all patients were treated by a single surgeon and received the same capsulotomy technique and postoperative protocol. Patients with a minimum 8-years follow-up, complete PROs, the presence of coxa profunda as indicated by the acetabular wall projecting medial to the ilioischial line, and a LCE angle > 40° were included (Figure 1). Patients with severe osteoarthritis (Tönnis osteoarthritis grade > 2) or any previous hip surgeries were excluded. Patients meeting inclusion and exclusion criteria represented the overcoverage cohort (OC) and were matched 1:1 by sex, age within 8 years, body mass index (BMI) within 5 kg/m2, Tönnis grade, and labral treatment (repair vs debridement) to a matched control (MC) cohort that had a LCE angle between 25° and 40°. Collected postoperative outcomes include conversion to THA, revision hip arthroscopy, patient satisfaction, pain level (0-100), number of corticosteroid injections, and 6 PROs (modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), Lower Extremity Functional Scale (LEFS), Hip Outcome Score (HOS)–Activities of Daily Living (HOS-ADL), HOS–Sports Specific subscale (HOS-SSS), and 33-item International Hip Outcome Tool (iHOT-33). Pearson χ2 test and Fisher exact test were used to compare categorical variables; two-sample t-tests were used to compare continuous variables. The threshold for statistical significance was set to 0.05. A survival analysis was performed using Kaplan-Meier curves. All statistical analyses were performed using Stata software (version 18.0; StataCorp). Results: A total of 38 patients in the OC cohort were 1:1 matched with 38 patients in the MC cohort. There were no differences in patient demographics including age, BMI, sex, Tönnis grade, labral treatment, follow-up duration, and Beck classification of labral damage or transition zone (chondrolabral junction) cartilage damage (Table 1). At an average of 11.3 years postoperatively (minimum 8-years follow-up), patients in the OC and MC cohort experienced similar rates of conversion to THA (OC: 11 [28.9%] vs MC: 6 [15.8%]; p = .169) and revision hip arthroscopy (OC: 4 [10.5%] vs MC: 1 [2.6%]; p = .165). The average time from primary hip arthroscopy to conversion to THA was 8.0 ± 6.5 years for OC and 3.7 ± 3.0 years for MC (p = .144) with the OC cohort converting to THA between 6.5 months to 17.14 years while the MC cohort ranged from 4.8 months to 7.8 years. Age at conversion to THA was 54.3 ± 8.0 years for the OC cohort and 59.0 ± 4.0 years for the MC cohort (p = .195). By Kaplan-Meier survival analysis, patients showed similar rates of survivorship (84.2%) at 12 years after hip arthroscopy; however, OC patients showed a 13.1% decrease in long-term survivorship (71.1%) between years 12 and 18 (Figure 2). Additionally, OC and MC patients showed similar levels of patient satisfaction, pain level, postoperative corticosteroid injections, and scores for all 6 PROs (Table 2). Conclusions: Patients with coxa profunda and overcoverage (LCE angle > 40°) showed similar levels of survivorship, revision arthroscopy, patient satisfaction, pain level, number of corticosteroid injections, and PROs to a 1:1 matched cohort of patients with normal acetabular coverage (LCE angle between 25° and 40°) at a minimum 8-years after primary hip arthroscopy. When analyzing long-term survivorship after 12 years, however, patients with overcoverage showed a 13.1% decrease in long-term survivorship (71.1%) compared to a matched control cohort. Overall, a greater focus on extended follow-up care after hip arthroscopy is needed to improve long-term survivorship in patients with a deep acetabular socket and pincer-type femoroacetabular impingement.

Incidence and management of secondary deformities after megaendoprosthetic proximal femur replacement in skeletally immature bone sarcoma patients

IntroductionMegaendoprosthetic reconstruction of bone defects in skeletally immature patients has led to the development of unique complications and secondary deformities not observed in adult patient cohorts. With an increasing number of megaendoprosthetic replacements performed, orthopedic oncologists still gain experience in the incidence and type of secondary deformities caused. In this study, we report the incidence, probable cause and management outcome of two secondary deformities after megaendoprosthetic reconstruction of the proximal femur: hip dysplasia and genu valgum.Materials and methodsRetrospective analysis of 14 patients who underwent primary and/or repeat reconstruction/surgery with a megaendoprosthetic proximal femur replacement between 2018 and 2022.ResultsMean patient age was 9.1 years (range 4–17 years). Stress shielding was observed in 71.4%. Hip dislocation was the most frequent complication (50%). While four dislocations occurred without an underlying deformity, secondary hip dysplasia was identified in 58.3% (n = 7/12) of intraarticular resections and reconstructions, leading to dislocation in 71.4% (n = 5/7). A genu valgum deformity was observed in 41.6% (n = 5/12). The incidence of secondary hip dysplasia and concomitant genu valgum was 42.9% (n = 3/7). Triple pelvic osteotomy led to rebound hip dysplasia in two cases (patients aged < 10 years), whereas acetabular socket replacement led to stable hip joints over the course of follow-up. Temporary hemiepiphyseodesis was applied to address secondary genu valgum.ConclusionsPatients aged < 10 years were prone to develop secondary hip dysplasia and genu valgum following proximal femur replacement in this study. Management of secondary deformities should depend on remaining skeletal growth. Stress shielding was observed in almost all skeletally immature patients.

Unaligned Hip Radiograph Assessment Utilizing Convolutional Neural Networks for the Assessment of Developmental Dysplasia of the Hip

Abstract Developmental dysplasia of the hip (DDH) is a condition in which the acetabular socket inadequately contains the femoral head (FH). If left untreated, DDH can result in degenerative changes in the hip joint. Several imaging techniques are used for DDH assessment. In radiographs, the acetabular index (ACIN), center-edge angle, Sharp's angle (SA), and migration percentage (MP) metrics are used to assess DDH. Determining these metrics is time-consuming and repetitive. This study uses a convolutional neural network (CNN) to identify radiographic measurements and improve traditional methods of identifying DDH. The dataset consisted of 60 subject radiographs rotated along the craniocaudal and mediolateral axes 25 times, generating 1500 images. A CNN detection algorithm was used to identify key radiographic metrics for the diagnosis of DDH. The algorithm was able to detect the metrics with reasonable accuracy in comparison to the manually computed metrics. The CNN performed well on images with high contrast margins between bone and soft tissues. In comparison, the CNN was not able to identify some critical points for metric calculation on a few images that had poor definition due to low contrast between bone and soft tissues. This study shows that CNNs can efficiently measure clinical parameters to assess DDH on radiographs with high contrast margins between bone and soft tissues with purposeful rotation away from an ideal image. Results from this study could help inform and broaden the existing bank of information on using CNNs for radiographic measurement and medical condition prediction.

A Cross Sectional Study of Early Detection of Developmental Dysplasia of Hip Joint by Ultrasonography in Infants below 90 days of Age

Hip dysplasia is an abnormality of the hip joint where the acetabular socket portion does not fully cover the ball portion of femoral head, resulting in an increased risk for joint dislocation. DDH ranges from a simple flattening of the acetabular cavity to the complete dislocation of the femoral head. If untreated, DDH can cause early hip osteoarthritis and, in the most severe forms, the presence of a limp with severe functional limitations, since walking age5.In the past, the incidence of severe forms of the disease without an early diagnosis program, was reported to be 0.13% of all newborns. Aim: To assess the usefulness of ultrasonography in early detection of Developmental Dysplasia of Hip joint in infants below 90 days of age. Material and Methods: A Cross sectional study was carried out under department of Radiology at a Tertiary rural health care centre. All neonates born in labor room and infants below 90 days of age receiving outpatient and inpatient care at tertiary rural health care centre fulfilling the inclusion criteria. Thus total 630 neonates were studied. Data were entered in EXCEL sheet and analysed using SSPS software version 20.0. Risk factors were presented and assessed by chi-square. Results: Majority 96.5% neonates had age less than 5 days. Mean age was 3.03+5.5 days, ranging between 1 Day to 86 days. On coronal- neutral HIP angle, on right mean alpha was 61.1 and beta was 61.5 and on left side mean alpha was 60.2 and beta was 62.9. Prevalence of Developmental Dysplasia of Hip joint was found to be 1.6%. Conclusion: Present study showed significance for gender, family history and gestational age. Present study concludes that USG can do early detection of DDH because Clinical presentation of DDH is little late. So for early diagnosis and treatment USG can be used as a screening test for all the newborns for DDH.

Can a Computational Model Predict the Effect of Lesion Location on Cam-type Hip Impingement?

The Warwick consensus defined femoroacetabular impingement syndrome as a motion-related clinical disorder of the hip with a triad of symptoms, clinical signs, and imaging findings representing symptomatic premature contact between the proximal femur and acetabulum. Several factors appear to cause labral and cartilage damage, including joint shape and orientation and patient activities. There is a lack of tools to predict impingement patterns in a patient across activities. Current computational modeling tools either measure pure ROM of the joint or include complexity that reduces reliability and increases time to achieve a solution. The purpose of this study was to examine the efficacy of a low computational cost approach to combining cam-type hip shape and multiple hip motions for predicting impingement. Specifically, we sought to determine (1) the potential to distinguish impingement in individual hip shapes by analyzing the difference between a cam lesion at the anterior femoral neck and one located at the superior femoral neck; (2) sensitivity to three aspects of hip alignment, namely femoral neck-shaft angle, femoral version angle, and pelvic tilt; and (3) the difference in impingement measures between the individual activities in our hip motion dataset. A model of the shape and alignment of a cam-type impinging hip was created and used to describe two locations of a cam lesion on the femoral head-neck junction (superior and anterior) based on joint shape information available in prior studies. Sensitivity to hip alignment was assessed by varying three aspects from a baseline (typical alignment described in prior studies), namely, femoral neck-shaft angle, femoral version, and pelvic tilt. Hip movements were selected from an existing database of 18 volunteers performing 13 activities (10 male, eight female; mean age 44 ± 19 years). A subset was selected to maximize variation in the range of joint angles and maintain a consistent number of people performing each activity, which resulted in nine people per activity, including at least three of each sex. Activities included pivoting during walking, squatting, and golf swing. All selected hip motion cases were applied to each hip shape model. For the first part of the study, the number of motion cases in which impingement was predicted was recorded. Quantitative analyses of the depth of penetration of the cam lesion into the acetabular socket and qualitative observations of impingement location were made for each lesion location (anterior and superior). In the second part of the study, in which we aimed to test the sensitivity of the findings to hip joint orientation, full analysis of both cam lesion locations was repeated for three modified joint orientations. Finally, the results from the first part of the analysis were divided by activity to understand how the composition of the activity dataset affected the results. The two locations of cam lesion generated impingement in a different percentage of motion cases (anterior cam: 56% of motion cases; superior cam: 13% of motion cases) and different areas of impingement in the acetabulum, but there were qualitatively similar penetration depths (anterior cam: 6.8° ± 5.4°; superior cam: 7.9° ± 5.8°). The most substantial effects of changing the joint orientation were a lower femoral version angle for the anterior cam, which increased the percentage of motion cases generating impingement to 67%, and lower neck-shaft angle for the superior cam, which increased the percentage of motion cases generating impingement to 37%. Flexion-dominated activities (for example, squatting) only generated impingement with the anterior cam. The superior cam generated impingement during activities with high internal-external rotation of the joint (for example, the golf swing). This work demonstrated the capability of a simple, rapid computational tool to assess impingement of a specific cam-type hip shape (under 5 minutes for more than 100 motion cases). To our knowledge, this study is the first to do so for a large set of motion cases representing a range of activities affecting the hip, and could be used in planning surgical bone removal. The results of this study imply that patients with femoroacetabular impingement syndrome with cam lesions on the superior femoral head-neck junction may experience impinging during motions that are not strongly represented by current physical diagnostic tests. The use of this tool for surgical planning will require streamlined patient-specific hip shape extraction from imaging, model sensitivity testing, evaluation of the hip activity database, and validation of impingement predictions at an individual patient level.

Proximal femoral varus osteotomy in Legg-Calve-Perthes disease

OperationszielDie proximale femorale Varisationsosteotomie (PVO) ist eine chirurgische Technik zur Rezentrierung des Hüftkopfes, sofern es bspw. im Rahmen der ablaufenden Legg-Calvé-Perthes(LCPD)-Krankheit zur Subluxation gekommen ist.IndikationenBis anhin existieren keine einheitlichen Indikationskriterien für die Containment-Therapie bei LCPD-Patienten. Einzelne, für die Deformitätsentwicklung prädiktive radiologische Faktoren, Alter bei Diagnosestellung oder Symptombeginn und Klassifikationen, welche die Pathomorphologie des Femurkopfes bezogen auf die Nekrose beschreiben, können die Indikationsstellung erleichtern.KontraindikationenDie absolute Kontraindikation stellt die Entwicklung eines Scharniergelenkes dar (Hinge-Abduktion). Bleibt der Femurkopf in einer Abduktionsröntgenaufnahme von 20° auch in Abwesenheit einer Hinge-Abduktion dezentriert oder besteht ein Total-Kopf-Befall, ergibt sich ebenfalls eine Kontraindikation. Relativ kontraindiziert ist die PVO bei Kindern mit Beginn der Erkrankung < 6 Jahren, in der Lateral-Pillar-Klassifikation Gruppe A soiwe bei I und II nach Catterall.OperationstechnikLateraler Standardzugang zum proximalen Femur. Platzieren des Anteversions-K-Drahtes ventral des Schenkelhalses. Weitere K-Drähte werden parallel mithilfe von Positionierinstrumenten in den Schenkelhals eingebracht. Der optimale Bereich für die Osteotomie wird aufgesucht. Für die Vereinfachung der Manipulation des distalen Fragments und als Referenz für die Derotation werden am Femurschaft weitere K‑Drähte eingebracht. Nach Femurosteotomie erfolgt proximales Fixieren der Platte durch sukzessives Auswechseln der K‑Drähte gegen winkelstabile Schrauben. Die interfragmentäre Kompression erzeugt eine exzentrisch positionierte Kortikalisschraube im mittleren distalen Plattenloch. Die weitere distale Fixation der Platte erfolgt mit winkelstabilen Schrauben. Auswechseln der Kortikalisschraube gegen eine weitere winkelstabile Schraube. Alternativ zur hier beschriebenen winkelstabilen Technik wurde früher meist mittels Winkelplatte korrigiert.WeiterbehandlungMobilisation unter Abrollbelastung an 2 Gehstöcken über 6 Wochen. Röntgenkontrolle und bei genügender Knochenkonsolidation Steigerung der Belastung. Implantatentfernung nach 9 bis 12 Monaten. Rückkehr zum Sport ab 3 Monaten.ErgebnisseDie PVO ist eine in der Behandlung von LCPD nahezu seit 60 Jahren angewendete und weltweit etablierte chirurgische Technik. Durch ein stetig wachsendes Verständnis der Grunderkrankung wird einerseits die Indikationsstellung für operative Interventionen optimiert. Andererseits tragen neue Implantate zur Verbesserung der klinisch-radiologischen Resultate und Verringerung von Komplikationen während und nach Operation bei.

In-line Pullout Strength of 2 Acetabular Fixation Methods for Ligamentum Teres Reconstruction of the Hip: A Cadaveric Study.

Background:Ligamentum teres (LT) reconstruction is an appropriate alternative in select cases of LT full-thickness tears, resulting in hip micro- or macroinstability. Graft fixation at the acetabular fossa is critical to achieving the best functional results.Purpose:The purpose of this study is to compare the pullout strength of 2 graft fixation methods used for LT reconstruction of the hip.Study Design:Controlled laboratory study.Methods:In 7 cadaveric specimens, the acetabular socket was prepared after the native LT was transected and the femoral head was removed. Seven separate tibialis anterior grafts were then prepared by suturing a running-locking No. 2 suture on each tail of the graft. Three specimens had fixation of the graft to the acetabulum using an adjustable cortical suspension suture button; the remaining 4 were fixed to the acetabulum using a knotless suture anchor. Specimens were then mounted onto a custom jig within a mechanical test frame to allow for the in-line pull of the graft fixation construct. After a preload of 5 N, each specimen was loaded to failure at 0.5 mm/s. Stiffness and load to failure were measured for each specimen construct.Results:Suture button fixation had a higher mean load to failure when compared with the knotless anchor fixation method (mean ± SD, 438.1 ± 114.3 vs 195.9 ± 50.0 N; P = .01). There was no significant difference in mean stiffness between the methods of fixation (24.5 ± 1.4 vs 26.5 ± 5.8 N/mm; P = .6).Conclusion:In this cadaveric study, the suture button fixation demonstrated greater load to failure than the knotless anchor fixation.Clinical Relevance:Results of this study can guide surgical decision making when selecting an acetabular fixation method for LT reconstruction.

Tailor-made design, fabrication and validation of SrO doped nanostructured ZTA ceramic Femoral head – Acetabular socket liner assembly

An established commercial grade SrO doped ZTA composition has been considered to design, fabrication through uniaxial pressing followed by sintering and polishing, validation of dimension, 3D surface profile, 3D microstructure, and compressive load bearing capacity of femoral head – acetabular socket liner prototypes for the hip prosthesis. While design and dimensions are concerned, both the steel (HRC60) molds were designed and machined to achieve precious dimensions of femoral head (FH; OD – 30 ± 0.01 mm) and acetabular socket liner (ASL; ID – 30.15 ± 0.01 mm). A close variation in the range of ±0.01 mm was confirmed the precision geometry of polished FH and ASL with consideration of 22 points coordinate measuring method (CMM). 3D surface profile ensures the surface characteristics of Ra = 0.2 ± 0.01 μm and Rq = 0.5 ± 0.01 μm for outer surface of FH and an inner surface of ASL, respectively. Structure integrity and fabrication defects including cracks and pores free bulk structures were confirmed by Micro CT. The compressive load resistance known as burst strength for independent FH and FH-ASL assembly were measured 16.2 KN and 17.6 KN, respectively. The developed ceramic prototypes have an economic advantage and can be adopted as artificial hip prosthesis after extensive in-vitro and in-vivo analysis.

Does increased acetabular depth affect safe infra-acetabular screw placement in acetabular fracture fixation?

BackgroundInfra-acetabular screws enhance the fixation strength in acetabular fractures with separation of both columns. Placement without iatrogenic femoral head violation is challenging.PurposeTo assess the impact of the acetabular configuration, the patients’ age and gender on safe infra-acetabulum screw insertion.MethodsIn 112 patients (69 females; mean age: 34 years, range 17–88; n = 200 hips), the lateral center–edge angle (LCE) was measured on radiographs. Using corresponding axial CT scans the residual distance from (the lateral border) of the screw to (the medial border of) the femoral head (“Screw-to-Femoral Head distance”; “RD_SFH”) was determined. Statistical analysis was carried out using linear regression, multiple linear regression and normal distribution estimation.ResultsThe mean (range) LCE angle was 30° (7°–51°) and the mean (range) “RD_SFH” was 5 mm (1–14 mm). The linear regression model shows a significant linear relation between LCE and “RD_SFH” with a slope parameter of − 0.15 (p value < 0.0001), the Pearson correlation between LCE and “RD_SFH” is − 0.56 (CI [− 0.71, [− 0.40]). Age did not have a significant impact on the relation between LCE and “RD_SFH” (p value 0.85). Compared to male patients, in females, the intercept is 4.62 mm (p value 0.0005) less, the slope parameter is 0.09 (p value 0.029) larger.ConclusionThe virtual possibility to place an infra-acetabular screw was given in all patients. An increasing depth of the acetabulum correlated with a decrease in residual distances. As hip joint cartilage thickness was not considered in measurements, intraoperative rule-out of screw mispositioning especially in deep acetabular sockets and females is still of utmost importance.

Differences between race and sex in measures of hip morphology: a population-based comparative study

This paper aims to (i) identify differences in measures of hip morphology between four racial groups using anteroposterior (AP) hip x-rays, and (ii) examine whether these differences vary by sex. 912 hip x-rays (456 individuals) from four racial groups (European Caucasians, American Caucasians, African Americans and Chinese) were obtained. Males and females (45-75 years) with no radiographic hip OA (Kellgren and Lawrence<Grade 2 or Croft<Grade 1) were included. Eleven features of hip joint morphology were analysed. Linear regression with generalised estimating equations (GEE) was used to determine race and sex differences in hip morphology. Post-hoc Bonferroni procedure was used to adjust for multiple comparisons. The final analysis included 875 hips. Chinese hips showed significant differences for the majority of measures to other racial groups. Chinese were characterised by more shallow and narrow acetabular sockets, reduced femoral head coverage, smaller femoral head diameter, and a lesser angle of alignment between the femoral neck and shaft. Variation was found between other racial groups, but with few statistically significant differences. The average of lateral centre edge angle, minimum neck width and neck length differed between race and sex (p-value for interaction<0.05). Significant differences were found in measures of morphology between Chinese hips compared to African Americans or Caucasian groups; these may explain variation in hip OA prevalence rates between these groups and the lower rate of hip OA in Chinese. Sex differences were also identified, which may further explain male-female prevalence differences for OA.

3D-additive deposition of an antibacterial and osteogenic silicon nitride coating on orthopaedic titanium substrate

A 3D-additive manufacturing approach produced a dense Si3N4 ceramic coating on a biomedical grade commercially pure titanium (cp-Ti) substrate by an automatic laser-sintering procedure. Si3N4 coatings could be prepared with thicknesses from the single to the tens of microns. A coating thickness, t = 15 ± 5 μm, was selected for this study, based on projections of homogeneity and scratching resistance. The Si3N4 coating met the 20 N threshold required for biomaterial applications, according to the standard scratch testing (ASTM C1624-05). The Si3N4 coating imparted both the antibacterial and osteogenic properties of bulk Si3N4 to the cp-Ti substrate. Both properties were comparable to those previously described for bulk Si3N4 biomedical implants. The newly developed Si3N4-coating was applied to commercially available Ti-alloy acetabular shells for total hip arthroplasty. A “glowing” test based on luciferase gene transformation was applied to visualize the colonization of gram-negative Escherichia coli on Si3N4-coated and uncoated Ti-alloy acetabular shells. The results showed that the coating technology conferred resistance to Staphylococcus epidermidis and Escherichia coli adhesion onto the bulk acetabular sockets.

Probing Local Mechanical Properties in Polymer-Ceramic Hybrid Acetabular Sockets Using Spherical Indentation Stress-Strain Protocols

Mechanical properties exhibited by the materials used in biomedical device components for articulating joints play an important role in determining the implant performance. In the fabrication of complex-shaped parts, the thermomechanical history experienced in different locations of the final part can be substantially dissimilar, which may lead to large differences in the local microstructures and properties. In many instances, it is not feasible to evaluate experimentally the local mechanical properties in the as-manufactured bioimplant prototypes using standardized tests, and use this information in refining the manufacturing cycle to develop implants with improved performance. In order to bridge this critical gap between materials development and manufacturing, we explore here the use of recently developed spherical indentation stress-strain analysis protocols for the mechanical characterization of local properties in the as-manufactured biomedical device prototype. More specifically, this paper presents two main advances: (i) extension of spherical indentation stress-strain analysis protocols needed to extract reliable estimates of elastic modulus and indentation yield strength from polymer matrix composite (PMC) samples and (ii) demonstration of the differences in the properties between samples produced specifically for the standard tension tests and the as-fabricated PMC acetabular socket prototype intended for total hip joint replacement applications. The results of the present study revealed large differences in the mean and variance of the measured moduli and indentation yield strengths in the acetabular socket and the tensile specimen. Based on the extensive micro-computed tomography (micro-CT) analysis, an attempt has been made to rationalize the local property differences on the basis of microstructural attributes.

Bone ongrowth of a cementless silver oxide-containing hydroxyapatite-coated antibacterial acetabular socket

BackgroundThe silver oxide-containing hydroxyapatite-coated socket (KYOCERA, Osaka, Japan) is a cementless antibacterial implant that has both the osteoconductivity of the HA and the antibacterial activity of silver. The silver oxide-containing hydroxyapatite coating was shown to have good osteoconductivity and new bone formation in vitro and in vivo. However, the histological bone ongrowth of this implant has not been proven in a clinical study. MethodsWe analyzed bone ongrowth using two silver oxide-containing hydroxyapatite-coated sockets that were removed in revision total hip arthroplasty for recurrent dislocation. A histomorphometric analysis was performed using a scanning electron microscope (SEM) connected to a CCD camera and an elemental analysis was performed by energy-dispersive elemental spectrometry (EDS). ResultA white structure thought to be osseous tissue was attached to the retrieved socket surface macroscopically, and histological bone ongrowth of the silver oxide-containing hydroxyapatite coating of the socket was confirmed by SEM. In addition, the presence of silver in the silver oxide-containing hydroxyapatite coating was confirmed in an elemental analysis by EDS. ConclusionHistologically, the silver oxide-containing hydroxyapatite-coated socket presented bone ongrowth in this clinical study.

Hip sonography screening - the basis for early developmental dysplasia detection and successful treatment

Introduction: Developmental dysplasia of the hip (DDH) is a wide spectrum of anomalies, ranging from simple instability with laxity of the articulation capsule to total dislocation of the femoral head from the acetabular socket. The development of the baby in the first months is very fast and the early diagnosis and the appropriate treatment is important for the successful outcome of the disease. Materials and Methods: Several infantile hip ultrasonography methods have been defined to assess the relationship between the femoral head and acetabulum. The method of Graf is the one that was defined first and is perhaps the most widely used. Reinhard Graf from Stolzalpe, Austria developed his technique in the late 1970s. The primary advantage of this method is that it has a standardised ex­amination technique, as well as a very well defined numeric hip typing system. It divides the joint in 4 types which correlate with the pathological changes. The ultrasound typing is based on a description of important elements of the acetabulum and measurement of two angles which quantify the bony ac­etabular roof and the cartilaginous acetabular roof. Throughout the years, a number of studies have shown the efficiency of the method of Graf in reducing the rate of late DDH and invalidity. Results: The study present the results of the screening and early treatment of DDH in the Department of Orthopaedics and traumatology - Medical University of Varna. The operative activity of this dis­ease has decreased substantially - from 2-3 per month in the late 90s, to 2-3 per year today. Conclusion: Early diagnosis and regular examinations lead to better and more effective treatment - by means of abduction gymnastics, abduction pants, and Pavlik harness. Thus the successful treat­ment of DDH depends on an early accurate diagnosis and an earlier start of the treatment.

Gestione dei difetti acetabolari: l’uso di osso omologo

Bone grafts are implanted materials that support or promote bone healing through an osteogenic, osteoconductive and/or osteoinductive mechanism to the local site. Acetabular bone deficiencies encountered during acetabular hip arthroplasty revision vary from cavitary or segmental defects to complete discontinuity. Several techniques exist to manage these defects. In this review we present the current surgical techniques for reconstructing the acetabular socket which includes a cementless acetabular component with morselised bone, structural allograft, reinforcement rings and bone cages. Segmental acetabular defects involving both columns with more than 50% of the graft supporting the cup suggest the application of ilioischial devices. The aim is to bridge areas of bone loss, providing immediate mechanical fixation. Acetabular reconstruction with the use of the antiprotrusion cage and allografts has to be considered as a reliable procedure to manage severe periprosthetic deficiencies with highly successful long-term outcomes in revision arthroplasty.

Highly Cross-linked Polyethylene Liner Dissociation from a Cement-less Modular Acetabular Shell: Two Case Reports.

Liner dissociation of polyethylene from a cementless acetabular socket following total hip arthroplasty (THA) is a rare complication. Cross-linked polyethylene liner dissociation from AMS-HA shell (KYOCERA Med, Osaka, Japan) occurred in 2 out of the 4153 (0.04%) cases approximately 10 years after undergoing surgery at our institute. First case was an 80-year-old female who underwent right THA along with subtrochanteric femoral shortening osteotomy due to complete dislocation hip, and second case was a 72-year-old male, who underwent right THA due to coxarthrosis. A 26 mm femoral head and CPE liner were used in both cases and the inclination degree of the acetabular socket was within 50°.There was no implant loosening in both cases. There was partial damage in the elevated rim on the alternative side and scratches on the back side in the both extracted CPE liner. It was surmised that liner dissociation was caused due to a problem in the liner fixing format of the push in type of the present model.

Preoperative Planning and Operative Techniques of the Shorter Tapered Stem Compared to the Metaphyseal Fit Stem in Cementless Total Hip Arthroplasty

BackgroundIn order to prevent postoperative dislocation due to prosthetic impingement as a result of total hip arthroplasty (THA), the combined anteversion (CA) theory, which combines the anteversion of the femoral stem and the acetabular socket, has been revised in recent years. Particularly, it is necessary to keep CA within the target zone. MethodsThe aim of this study was to investigate whether postoperative CA can be kept within the target zone while using the operative technique which prepares the socket first in cementless THA, by estimating the anteversion of the metaphyseal fit stem or the shorter, tapered wedge stem using preoperative 3-dimensional computerized planning, and by adjusting the anteversion of the socket using a navigation system that considers CA. One hundred fourteen patients (118 hips) were recruited for the study. ResultsPostoperative CA in THA using the metaphyseal fit stem was kept within the target zone for 56 of the 60 hips (93.3%). Using the shorter, tapered wedge stem, 49 of the 58 hips (84.4%) were within the target zone. No postoperative dislocations were observed in any hips. ConclusionWe found that the metaphyseal fit stem worked better than the shorter, tapered wedge stem in terms of meeting the planned CA. The shorter, tapered wedge stems were flexible in rotation according to the anatomical configuration of the proximal femur. Therefore, the stem could be placed second with the metaphyseal fit stem, but we recommend placing the stem first with the shorter, tapered wedge stem.

How common it is? How often we miss it????

Background: Coxa profunda or deep acetabular socket is a variant of cam type of femoroacetabular impingement (FAI). It is a common radiographic finding in patients with painful hip which is often missed. The diagnosis of this condition plays a vital role in the approach towards the treatment and functional outcome of the treatment. The purpose of this study is to determine the prevalence of coxa profunda. Materials and Methods: In this study a total of 117 pelvis with bilateral radiographs out of which 77 patients with positive radiographic findings for coxa profunda are analysed retrospectively. The study was done at R.L. Jalappa Hospital and Research Centre, Tamaka. Kolar. Patients with positive radiographic findings are called and taken thorough history and examination done to know whether patients are symptomatic or not. Results: Among 117 patient radiographs taken for the study 77 patients are diagnosed with coxa profunda. The results were analysed on clinical findings like positive stress test for pincer type of femoroacetabular index and also parameters like medialization of floor of fossa acetabuli, increase in lateral centre edge angle(CE), decrease in acetabular index (tonni’s angle),decrease in femoral head extrusion index, femoral acetabular over coverage are taken into consideration for the diagnosis of this condition. Conclusion: Coxa profunda is a common variation of pincer type of femoroacetabular impingement which is often missed.

An unusual presentation of catastrophic failure of hip arthroplasty with a thigh mass

In the advent of increasing demand for total hip arthroplasty, surveillance of these patients is imperative to identify potential complications requiring revision surgery. This is especially important in the young population, as revision is usually necessary during their lifetime. We present a case of a young female patient with a history of total hip arthroplasty 17 years prior, who presented with left hip pain and anterior thigh mass. The prosthetic hip had progressed to catastrophic failure with the cobalt-chrome femoral head having eroded through the polyethylene and acetabular socket. This was associated with significant metal debris and large fluid collection in the thigh. The patient required complex revision surgery but could have had a much lesser procedure with earlier intervention.