Aim: The aim of this study was to determine if a correlation exists between the impingement test and the arthroscopic findings at the
Radiodense structures resembling ossicles at the
Purpose of the study: The anterior rim of the arthroplasty cup can overhang the bone in certain situations: oversized cup, insufficient anteversion, insufficient ace-tabular reaming, cylindrospherical reaming overriding the acetabular opening. The straight or concave shape of the anterior wall of the acetabulum also affects prosthetic overhang. The purpose of this anatomic study was to use a navigation system to quantify, in vitro, the height of the iliopubic psoas notch. Material and methods: Sixty-eight acetabuli from 34 cadaver pelvi free of osteoarthritis (13 male and 21 female) were analyzed using the Stryker™ hip navigation system. Morphological data were collected for mathematical processing which defined the diameter and the center of the articular surface. Results: Considerable intra- and inter-individual differences in the shape of the
The
Introduction. Ectopic ossification (EO) at the
Purpose. The effects of
Hip arthroscopy has gained prominence as a primary surgical intervention for symptomatic femoroacetabular impingement (FAI). This study aimed to identify radiological features, and their combinations, that predict the outcome of hip arthroscopy for FAI. A prognostic cross-sectional cohort study was conducted involving patients from a single centre who underwent hip arthroscopy between January 2013 and April 2021. Radiological metrics measured on conventional radiographs and magnetic resonance arthrography were systematically assessed. The study analyzed the relationship between these metrics and complication rates, revision rates, and patient-reported outcomes.Aims
Methods
Retrieval investigations have shown that cracking or rim failure of polyethylene hip liners may occur at the superior aspect of the liner, in the area that engages the locking ring of the shell1. Failure could occur due to acetabular liner/stem impingement and/or improper cup position. Other contributing factors may include high body mass index, patient activity and design characteristics such as polyethylene material properties, thin liner rim geometry and cup rim design. Currently no standard multi-axis simulator methodology exists for high angle rim fatigue testing, although tests have been developed using static uniaxial load frames2. The purpose of this study was to develop a technique to create a clinically relevant rim crack/fracture event on a 4-axis hip simulator, and to understand the contribution of component design and loading and motion parameters. A method for creating rim fracture Introduction
Method
Within total hip replacement, articulation of the femoral head near the rim of the acetabular liner creates undesirable conditions leading to a propensity for dislocation[1], increased contact stresses[2], increased load and torque imparted on the acetabular component[3], and increased wear[4]. Propensity for rim loading is affected by prosthesis placement, as well as the kinematics and loading of the patient. The present study investigates these effects. CT scans from an average-sized patientwere segmented for the hemipelvis and femur of interest. DePuy Synthes implant models were aligned in a neutral position in Hypermesh. The acetabular liner was assigned deformable solid material properties, and the remainder of the model was assigned rigid properties. Joint reaction forces and kinematics of hip flexion were taken from the public Orthoload database to represent ADLs [5]: Active flexion lying on a table, gait, bending to lift and move a load, and sit-stand. The pelvis was fully constrained, while three-degree-of-freedom (3-DOF) forces were applied to the femur. Hip flexion was kinematically-prescribed while internal-external (I-E) and adduction-abduction (Ad-Ab) DOFs were constrained. Angles of acetabular implant positioning were based on published data by Rathod [6]. Femoral implant position was chosen based on cadaveric in vitro DePuy Synthes measurements of variation in femoral prosthesis position reported previously [7]. Acetabular and Femoral alignment angles were represented for nominal position, as well as positioning + 1σ and + 2σ from the mean in both anteversion and inclination for acetabular components, and both Varus/Valgus and Flexion (angle in sagittal plane) for the femoral component. The analyses were automated within Matlab to execute 68 finite element analyses in Abaqus Explicit and structured in a DOE style analysis with Cup inclination, Cup version, Stem Flexion, and Stem Varus/Valgus, and Activity as variables of interest (64 runs + 4 centerpoints = 68 analyses). From a previous study it was known that acetabular component inclination had the greatest effect on contact pressure location [7], so all data were analyzed relative to inclination, allowing other positioning variables to be represented as variation per inclination position. Results are presented as a percentage, with 0% being pole loading and 100% being rim loading, to normalize for head diameter.INTRODUCTION
METHODS
The results showed that in all rim supported conditions, the maximum principal stress were in compressive patterns, a preferred pattern to reduce the potential polyethylene liner fracture. In rim unsupported conditions, the stresses was in tensile on the internal bearing surface when polyethylene liner thickness was bellow 5 mm, or was bellow 9 mm if the average maximum principal stress cross the rim was considered. We conclude that the metal rim support changes the stress pattern in the rim region of UHMWPE liner to compressive for all liner thicknesses. The stress pattern turns to tensile, or there will be a higher potential for rim fracture, if UHMWPE liner is unsupported and the polyethylene rim thickness is less than 9 mm. Although components used this study did not include the locking details which add higher stress concentrations, the trend of stress patterns should follow the results found in this study.
Previous studies suggested the lack of capture wall of acetabular Ultra High Molecular Weight Polyethylene (UHMWPE) liner can significantly increase the risk of hip joint dislocation. To date, the dislocation studies have been focused on the femoral neck impingement models. The purpose of this study was to identify a new Dislocating Force (DF) generated by rim directed joint force alone and investigate the factors to affect the magnitudes of the DF. The 3 D Finite Element Analysis (FEA) models were constructed by (30) 10 mm thick UHMWPE liners with six inner bearing diameters ranging from 22 mm to 44 mm and five capture wall heights in each bearing size from 0 mm to 2 mm. A load of 2 446 N was applied through the corresponding CoCr femoral head to the rim of the liner. The DF was recorded as a function of capture wall height and head diameter. The results were verified by the physical tests of two 28 mm head bearing liners with 0 and 1.5 mm capture wall heights respectively. The results showed that the highest DF was 1 269N in 0 mm capture wall and 22 mm head. The lowest DF was 171 N in 2 mm capture wall and 44 mm head. The DF decreased as the capture wall and head size increased. When capture wall increased from 0 mm to 1 mm, the DF was reduced more than 50%. Two experimental data points were consistent with the trend of DF curve found in the FEA. We concluded that the new intrinsic dislocating force DF can be induced by the rim directed joint loading force alone and can reach as high as 51% of the femoral loading force. A capture wall height above 1mm can effectively reduce DF to less than 25% of the joint force. In addition, the larger head diameter also resulted in less DF generation.
Cam-type femoroacetabular impingement is caused by bone excess on the femoral neck abutting the
Aims. Research on hip biomechanics has analyzed femoroacetabular contact pressures and forces in distinct hip conditions, with different procedures, and used diverse loading and testing conditions. The aim of this scoping review was to identify and summarize the available evidence in the literature for hip contact pressures and force in cadaver and in vivo studies, and how joint loading, labral status, and femoral and acetabular morphology can affect these biomechanical parameters. Methods. We used the PRISMA extension for scoping reviews for this literature search in three databases. After screening, 16 studies were included for the final analysis. Results. The studies assessed different hip conditions like labrum status, the biomechanical effect of the cam, femoral version, acetabular coverage, and the effect of rim trimming. The testing and loading conditions were also quite diverse, and this disparity limits direct comparisons between the different researches. With normal anatomy the mean contact pressures ranged from 1.54 to 4.4 MPa, and the average peak contact pressures ranged from 2 to 9.3 MPa. Labral tear or resection showed an increase in contact pressures that diminished after repair or reconstruction of the labrum. Complete cam resection also decreased the contact pressure, and
Femoroacetabular impingement (FAI) results from a morphological deformity of the hip and is associated with osteoarthritis (OA). Increased bone mineral density (BMD) is observed in the antero-superior acetabulum rim where impingement occurs. It is hypothesized that the repeated abnormal contact leads to damage of the cartilage layer, but could also cause a bone remodelling response according to Wolff's Law. Thus the goal of this study was to assess the relationship between bone metabolic activity measured by PET and BMD measured in CT scans. Five participants with asymptomatic cam deformity, three patients with uni-lateral symptomatic cam FAI and three healthy controls were scanned in a 3T PET-MRI scanner following injection with [18F]NaF. Bone remodelling activity was quantified with Standard Uptake Values (SUVs). SUVmax was analyzed in the antero-superior
Femoroacetabular impingement (FAI) deformities are a potential precursor to hip osteoarthritis and an important contributor to non-arthritic hip pain. Some hips with FAI deformities develop symptoms of pain in the hip and groin that are primarily position related. The reason for pain generation in these hips is unclear. Understanding potential impingement mechanisms in FAI hips will help us understand pain generation. Impingement between the femoral head-neck contour and
Aims. Cam and pincer morphologies are potential precursors to hip osteoarthritis and important contributors to non-arthritic hip pain. However, only some hips with these pathomorphologies develop symptoms and joint degeneration, and it is not clear why. Anterior impingement between the femoral head-neck contour and
Aims. The effect of pelvic tilt (PT) and sagittal balance in hips with pincer-type femoroacetabular impingement (FAI) with acetabular retroversion (AR) is controversial. It is unclear if patients with AR have a rotational abnormality of the iliac wing. Therefore, we asked: are parameters for sagittal balance, and is rotation of the iliac wing, different in patients with AR compared to a control group?; and is there a correlation between iliac rotation and acetabular version?. Methods. A retrospective, review board-approved, controlled study was performed including 120 hips in 86 consecutive patients with symptomatic FAI or hip dysplasia. Pelvic CT scans were reviewed to calculate parameters for sagittal balance (pelvic incidence (PI), PT, and sacral slope), anterior pelvic plane angle, pelvic inclination, and external rotation of the iliac wing and were compared to a control group (48 hips). The 120 hips were allocated to the following groups: AR (41 hips), hip dysplasia (47 hips) and cam FAI with normal acetabular morphology (32 hips). Subgroups of total AR (15 hips) and high acetabular anteversion (20 hips) were analyzed. Statistical analysis was performed using analysis of variance with Bonferroni correction. Results. PI and PT were significantly decreased comparing AR (PI 42° (SD 10°), PT 4° (SD 5°)) with dysplastic hips (PI 55° (SD 12°), PT 10° (SD 6°)) and with the control group (PI 51° (SD 9°) and PT 13° (SD 7°)) (p < 0.001). External rotation of the iliac wing was significantly increased comparing AR (29° (SD 4°)) with dysplastic hips (20°(SD 5°)) and with the control group (25° (SD 5°)) (p < 0.001). Correlation between external rotation of the iliac wing and acetabular version was significant and strong (r = 0.81; p < 0.001). Correlation between PT and acetabular version was significant and moderate (r = 0.58; p < 0.001). Conclusion. These findings could contribute to a better understanding of hip pain in a sitting position and extra-articular subspine FAI of patients with AR. These patients have increased iliac external rotation, a rotational abnormality of the iliac wing. This has implications for surgical therapy with hip arthroscopy and
Introduction. Malalignment of cup in total hip replacement (THR) increases rates of dislocation, impingement, acetabular migration, pelvic osteolysis, leg length discrepancy and polyethylene wear. Many surgeons orientate the cup in the same anteversion and inclination as the inherent anatomy of the acetabulum. The transverse acetabular ligament (TAL) and
To quantify the acetabular coverage of the femoral head, Lequesne's vertical-center-anterior edge (VCA) angle is used on the false profile view. Lateral coverage is determined by Wiberg's lateral-center-edge (LCE) angle on an ap pelvic view. The delimitation of the weightbearing area is defined by the end of the subchondral sclerosis line for both views. To our knowledge the exact anatomic location of the points used for measurement on the
Mixed Reality has the potential to improve accuracy and reduce required dissection for the performance of peri-acetabular osteotomy. The current work assesses initial proof of concept of MR guidance for PAO. A PAO planning module, based on preoperative computed tomography (CT) imaging, allows for the planning of PAO cut planes and repositioning of the acetabular fragment. 3D files (holograms) of the cut planes and native and planned acetabulum positions are exported with the associated spatial information. The files are then displayed on mixed reality head mounted device (HoloLens2, Microsoft) following intraoperative registration using an FDA-cleared mixed reality application designed primary for hip arthroplasty (HipInsight). PAO was performed on both sides of a bone model (Pacific Research). The osteotomies and acetabular reposition were performed in accordance with the displayed holograms. Post-op CT imaging was performed for analysis. Cutting plane-accuracy was evaluated using a best-fit plane and 2D angles (°) between the planned and achieved supra (SA)- and retroacetabular (RA) osteotomy and retroacetabular and ischial osteotomies (IO) were measured. To evaluate the accuracy of acetabular reorientation, we digitized the
We examined the relationship between the size
of the femoral cam in femoroacetabular impingement (FAI) and acetabular
pathomorphology to establish if pincer impingement exists in patients
with a femoral cam. CT scans of 37 symptomatic impinging hips with a femoral cam
were analysed in a three-dimensional study and were compared with
34 normal hips. The inclination and version of the acetabulum as
well as the
INTRODUCTION. Mal-positioning of the acetabular component in total hip replacement (THR) could lead to edge loading, accelerated component wear, impingement and dislocation [1,2]. In order to achieve a successful position for the acetabular component, the assessment of the acetabular orientation with reference to different coordinate systems is important [3]. The aims of the present study were to establish a pelvic coordinate system and a global body coordinate system, and to assess the acetabular orientations of natural hips with reference to the two coordinate systems. METHODS. Three-dimensional (3D) computed tomographic (CT) images of 56 subjects (28 males and 28 females) lying supine were obtained from a public image archive (Cancer Image Archive, website: . www.cancerimagingarchive.net. ). 3D solid models of pelvis and spine were generated from the CT images. Two coordinate systems, pelvic and global body coordinate systems, were established. The pelvic coordinate system was established based on four bony landmarks on the pelvis: the bilateral anterior superior iliac spines (RASIS and LASIS) and the bilateral pubic tubercles (RPT and LPT). The global body coordinate system was generated based on the bony landmarks on the spine: the geometric centers of five lumbar vertebrae bodies and the most dorsal points of five corresponding spinous processes, as well as the anterior sacral promontory (Fig 1a and 1b). The
Arthroscopic management of femoroacetabular impingement (FAI) has become the mainstay of treatment. However, chondral lesions are frequently encountered and have become a determinant of less favourable outcomes following arthroscopic intervention. The aim of this systematic review and meta-analysis was to assess the outcomes of hip arthroscopy (HA) in patients with FAI and concomitant chondral lesions classified as per Outerbridge. A systematic search was performed using the PRISMA guidelines on four databases including MEDLINE, EMBASE, Cochrane Library and Web of Science. Studies which included HA as the primary intervention for management of FAI and classified chondral lesions according to the Outerbridge classification were included. Patients treated with open procedures, for osteonecrosis, Legg-Calve-Perthes disease, and previous ipsilateral hip fractures were excluded. From a total of 863 articles, twenty-four were included for final analysis. Demographic data, PROMs, and radiological outcomes and rates of conversion to total hip arthroplasty (THA) were collected. Risk of bias was assessed using ROBINS-I. Improved post-operative PROMs included mHHS (mean difference:-2.42; 95%CI:-2.99 to −1.85; p<0.001), NAHS (mean difference:-1.73; 95%CI: −2.23 to −1.23; p<0.001), VAS (mean difference: 2.03; 95%CI: 0.93-3.13; p<0.001). Pooled rate of revision surgery was 10% (95%CI: 7%-14%). Most of this included conversion to THA, with a 7% pooled rate (95%CI: 4%-11%). Patients had worse PROMs if they underwent HA with labral debridement (p=0.015), had Outerbridge 3 and 4 lesions (p=0.012), concomitant lesions of the femoral head and acetabulum lesions (p=0.029). Reconstructive cartilage techniques were superior to microfracture (p=0.042). Even in concomitant lesions of the femoral head and acetabulum, employing either microfracture or cartilage repair/reconstruction provided a benefit in PROMs (p=0.027). Acceptable post-operative outcomes following HA with labral repair/reconstruction and cartilage repair in patients with FAI and concomitant moderate-to-severe chondral lesions, can be achieved. Patients suffering from Outerbridge 3 and 4 lesions, concomitant
Introduction: There have been several recent studies outlining the role of femoroacetabular impingement (FAI) as a cause of early osteoarthritis in the non-dysplastic hip. The lesions can either be on the femoral side “cam” or acetabular “pincer”. The aim of surgical treatment of FAI is to improve the femoral head neck offset thereby improving joint clearance and preventing abutment of the femoral neck against the acetabulum. The classic treatment for FAI pioneered by Ganz involves dislocation of the femoral head through a trochanteric flip osteotomy. The procedure is extensive, technically difficult and not without complications. Hip arthroscopic debridement of FAI lesions offers similar results to open procedures allowing for full inspection of the joint and the treatment of any chondral lesion but with a quicker recovery time. It nonetheless has a very long learning curve and even in the most experienced hands the treatment of impingement lesions is complicated and technically challenging. The purpose of this cadaveric study was to assess the degree of exposure obtained using two different limited anterior approaches to the hip which would allow effective surgical treatment of cam and pincer FAI. Methods: We investigated two mini anterior approaches to the hip joint based on the Heuter and direct anterior approach to compare the parts of the acetabulum and femoral head exposed for the treatment of FAI in a total of 20 hips in 10 (5 male, 5 female) cadaveric specimens. Neurovascular structures were recorded in relation to the two approaches. The area of femoral head and
Introduction and Objective. To estimate the prevalence of acetabular ossifications in the adult population with asymptomatic, morphologically normal hips at CT and to determine whether the presence of labral ossifications is associated with patient-related (sex, age, BMI), or hip-related parameters (joint space width, and cam- and pincer-type femoroacetabular impingement morphotype). Materials and Methods. We prospectively included all patients undergoing thoracoabdominal CT over a 3-month period. After exclusion of patients with a clinical history of hip pathology and/or with signs of osteoarthritis on CT, we included a total of 150 hips from 75 patients. We analyzed the presence and the size of labral ossifications around the
Introduction. Optimal orientation of the acetabular cup is vital issue not only for primary but revision total hip arthroplasty (THA). Especially in revision THA, malorientation of the cup is likely to occur because anatomical landmark around
Cam femoroacetabular impingement (FAI) is currently treated by resecting the femoral cam lesion. Some surgeons advocate additional anterosuperior
Cam-type femoroacetabular impingement (cam-FAI) can be treated with femoral neck osteochondroplasty to increase the clearance between the femoral head/neck and the
Lesions of the
Major bone loss involving the acetabulum can be seen during revision THA due to component loosening, migration or osteolysis and can also occur as a sequela of infected THA. Uncemented porous ingrowth components can be used for reconstruction of the vast majority of revision cases, where smaller segmental or cavitary defects are typically present. But when stable structural support on host bone is lacking, highly porous metal acetabular augments have been described as an alternative to large structural allograft. The fundamental concept behind these acetabular augments is the provision of critical additional fixation, structural support and increased contact area against host bone over the weeks following surgery while the desired ingrowth into porous implant surfaces is occurring. Three separate patterns of augment placement have been utilised in our practice since the development of these implants a decade ago: Type 1 - augment screwed onto the superolateral
Introduction. In recent years, there has been a significant advancement in our understanding of femoro-acetabular impingement and associated labral and chondral pathology. Surgeons worldwide have demonstrated the successful treatment of these lesions via arthroscopic and open techniques. The aim of this study is to validate a simple and reproducible classification system for acetabular chondral lesions. Methods. In our classification system, the acetabulum is first divided into 6 zones as described by Ilizalithurri VM et al [Arthroscopy 24(5) 534-539]. The cartilage is then graded as 0 to 4 as follows: Grade 0 – normal articular cartilage lesions; Grade 1 softening or wave sign; Grade 2 - cleavage lesion; Grade 3 - delamination and Grade 4 –exposed bone. The site of the lesion is further typed as A, B or C based on whether the lesion is 1/3 distance from
Introduction:. The transverse acetabular ligament (TAL) antomy is not a well explored aspect of the hip joint with limited morphological description in the reviewed literature. It is often used as an anatomical landmark for orientation of the acetabular component in total hip arthroplasty (THA). There is debate as to whether it represents an appropriate guide to cup placement in THA. Present descriptions in orthopaedic literature conside it as a single plane structure to which the surgeon can align the cup. The aim of the current study was to investigate the morphology of the TAL and it was hypothesised that the current description of it being a plane would prove insufficient. Materials and methods:. Seven dry bone hemi-pelves were reconstructed using a microscribe and rhinoceros 4.0 3D software to visualise attachment sites. Three hips from two female donors were dissected to expose the acetabulum and the TAL. This structure was removed and a footprint taken of its perimeter and attachment sites for measurement of ligament length, breadth and area of attachment from digital photographs. Finally, 3D models of the dissected acetabuli with an outline of the TAL and attachment sites were created as before. Results:. The TAL extended beyond the acetabular notch, around the circumference of the
Background. Femoro-acetabular impingement (FAI) is increasingly recognised as a cause of mechanical hip symptoms in sportspersons. In femoro-acetabular impingement abnormal contact occurs between the proximal femur and the
Introduction: In recent years, there has been a significant advancement in our understanding of femoro-acetabular impingement and associated labral and chondral pathology. Surgeons worldwide have demonstrated the successful treatment of these lesions via arthroscopic and open techniques. The aim of this study is to validate a simple and reproducible classification system for acetabular chondral lesions. Methods: In our classification system, the acetabulum is first divided into 6 zones as described by Ilizalithurri VM et al [Arthroscopy 24(5) 534–539]. The cartilage is then graded as 0 to 4 as follows: Grade 0 – normal articular cartilage lesions; Grade 1 softening or wave sign; Grade 2 – cleavage lesion; Grade 3 – delamination and Grade 4 -exposed bone. The site of the lesion is further typed as A, B or C based on whether the lesion is 1/3 distance from
Abstract. Background. Optimal acetabular component position in Total Hip Arthroplasty is vital for avoiding complications such as dislocation, impingement, abductor muscle strength and range of motion. Transverse acetabular ligament (TAL) and posterior labrum have been shown to be a reliable landmark to guide optimum acetabular cup position. There have been reports of iliopsoas impingement caused by both cemented and uncemented acetabular components. Acetabular component mal-positioning and oversizing of acetabular component are associated with iliopsoas impingement. The Psoas fossa (PF) is not a well-regarded landmark to help with Acetabular Component positioning. Our aim was to assess the relationship of the TAL and PF in relation to Acetabular Component positioning. Methods. A total of 12 cadavers were implanted with the an uncemented acetabular component, their position was initially aligned to TAL. Following optimal seating of the acetabular component the distance of the rim of the shell from the PF was noted. The Acetabular component was then repositioned inside the PF to prevent exposure of the rim of the Acetabular component. This study was performed at Smith & Nephew wet lab in Watford. Results. Out of the twelve acetabular components that were implanted parallel to the TAL, all had the
Introduction. Geometric variations of the hip joint can give rise to repeated abnormal contact between the femur and
Background: Femoro-acetabular impingement (FAI) is increasingly recognised as a cause of mechanical hip symptoms in sportspersons. In femoro-acetabular impingement abnormal contact occurs between the proximal femur and the
The acetabular labrum is a soft-tissue structure
which lines the
The present study investigates the repeatability of two new methods of measuring acetabular wear with differing levels of automation. Experimental evaluation showed that the more automated method was more repeatable. Both methods segmented the femoral head and
Pincer femoroacetabular impingement (FAI) is cited as being the result of a socket that is either too deep or retroverted, or both. Using 3D-CT analysis, we set out to quantify the
Standard evaluation and diagnosis of pincer-type femoroacetabular impingment (FAI) relies on anteroposterior (AP) radiographs, clinical evaluation, and/or magnetic resonance imaging (MRI). However, the current evaluation techniques do not offer a method for accurately defining the amount of
Hip impingement is a diagnosis that has been increasingly recognized among young patients with hip pain. Two different types of impingement have been described. Over coverage impingement, or a “pincer” effect, occurs between the anterior wall or labrum of the acetabulum and the femoral head. This is typically due to a decrease in anteversion of the acetabulum or over-coverage of the femoral head (coxa profunda or protrusio). A so-called cam-effect impingement occurs when the femoral head-neck junction has an abnormally large radius resulting in insufficient offset. Widening of the femoral neck reduces its concavity, creating an impingement over the
Introduction. The Exeter RimFit™ flanged cemented cup features ultra-highly cross-linked polyethylene and was introduced onto the market in the UK in 2010. We aimed to examine the rates of radiolucent lines observed when the Rimfit™ cup was implanted using a ‘rimcutter’ technique with the cup sitting on a prepared
Major bone loss involving the acetabulum can be seen during revision THA due to component loosening, migration or osteolysis and can also occur as a sequela of infected THA. Uncemented porous ingrowth components can be used for reconstruction of the vast majority of revision cases, where smaller segmental or cavitary defects are typically present. But when stable structural support on host bone is lacking, highly porous metal acetabular augments have been described as an alternative to large structural allograft, avoiding the potential for later graft resorption and the resulting loss of mechanical support that can follow. The fundamental concept behind these acetabular augments is the provision of critical additional fixation, structural support and increased contact area against host bone over the weeks following surgery while the desired ingrowth into porous implant surfaces is occurring. Three separate patterns of augment placement have been utilised in our practice since the development of these implants a decade ago: Type 1 – augment screwed onto the superolateral
To assess the current literature on suture anchor placement for the purpose of identifying factors that lead to suture anchor perforation and techniques that reduce the likelihood of complications. Three databases (PubMed, Ovid MEDLINE, EMBASE) were searched, and two reviewers independently screened the resulting literature. Methodological quality of all included papers was assessed using Methodological Index for Non-Randomized Studies criteria and the Cochrane Risk of Bias Assessment tool. Results are presented in a narrative summary fashion using descriptive statistics. Fourteen studies were included in this review. Four case series (491 patients, 56.6% female, mean age 33.9 years), nine controlled cadaveric/laboratory studies (111 cadaveric hips and 12 sawbones, 42.2% female, mean age 60.0 years), and one randomized controlled trial (37 hips, 55.6% female, mean age 34.2 years) were included. Anterior cortical perforation by suture anchors led to pain and impingement of pelvic neurovascular structures. The anterior acetabular positions (three to four o'clock) had the thinnest bone, smallest rim angles, and highest incidence of articular perforation. Drilling angles from 10° to 20° measured off the coronal plane were acceptable. The mid-anterior (MA) and distal anterolateral (DALA) portals were used successfully, with some studies reporting difficulty placing anchors at anterior locations via the DALA portal. Small-diameter (< 1 .8-mm) suture anchors had a lower in vivo incidence of articular perforation with similar stability and pull-out strength in biomechanical studies. Suture anchors at anterior
Major bone loss involving the acetabulum can be seen during revision THA due to component loosening, migration or osteolysis and can also occur as a sequela of infected THA. Uncemented porous ingrowth components can be used for reconstruction of the vast majority of revision cases, where smaller segmental or cavitary defects are typically present. But when stable structural support on host bone is lacking, highly porous metal acetabular augments have been described as an alternative to large structural allograft, avoiding the potential for later graft resorption and the resulting loss of mechanical support that can follow. The fundamental concept behind these acetabular augments is the provision of critical additional fixation, structural support and increased contact area against host bone over the weeks following surgery while the desired ingrowth into porous implant surfaces is occurring. Technique: Three separate patterns of augment placement have been utilised in our practice since the development of these implants: Type 1 - augment screwed onto the superolateral
The β-angle is a radiological tool for measuring the distance between the pathological head-neck junction and the
Recently, femoroacetabular impingement has been recognised as a cause of early osteoarthritis. There are two mechanisms of impingement: 1) cam impingement caused by a non-spherical head and 2) pincer impingement caused by excessive acetabular cover. We hypothesised that both mechanisms result in different patterns of articular damage. Of 302 analysed hips only 26 had an isolated cam and 16 an isolated pincer impingement. Cam impingement caused damage to the anterosuperior acetabular cartilage with separation between the labrum and cartilage. During flexion, the cartilage was sheared off the bone by the non-spherical femoral head while the labrum remained untouched. In pincer impingement, the cartilage damage was located circumferentially and included only a narrow strip. During movement the labrum is crushed between the
HXLPE acetabular liners were introduced to reduce wear-related complications in THA. However, post-irradiation thermal free radical stabilization can compromise mechanical properties, leave oxidation-prone residual free radicals, or both. Reports of mechanical failure of HXLPE
Optimal alignment of the acetabular cup component is crucial for good outcome of total hip arthroplasty [THA]. Increased accuracy of implant positioning may improve clinical outcome. To achieve this, patient specific instrumentation was developed. A patient-specific guide manufactured by 3D printing was designed to aid in positioning of the cup component with a pre-operatively defined anteversion and inclination angle. The guide fits perfectly on the