We carried out
Rotational acetabular osteotomy (RAO), one of periacetabular osteotomies, is an effective joint-preserving surgical treatment for developmental dysplasia of the hip. Since 2013, we have been using a CT-based navigation for RAO to perform safe and accurate osteotomy. CT-based navigation allows precise osteotomy during surgery but cannot track the bony fragment after osteotomy. Thus, it is an issue to achieve successful reorientation in accordance with preoperative planning. In this presentation, we introduce a new method to achieve reorientation and evaluate its accuracy. Thirty joints in which CT-based navigated RAO was performed were included in this study. For the first 20 joints, reorientation was confirmed by tracing the lateral aspect of rotated fragment with navigation and checked if it matched with the preoperative planning. For the latter 10 joints, a new method was adopted. Four fiducial points were made on lateral side of the acetabulum in the preoperative 3-dimensional model and intraoperatively, rotation of the osteotomized bone was performed so that the 4 fiducial points match the preoperative plan. To assess the accuracy of position of rotated fragment in each group, preoperative planning and postoperative CT were compared. A total of 24
Aims. To evaluate how abnormal proximal femoral anatomy affects different femoral version measurements in young patients with hip pain. Methods. First, femoral version was measured in 50 hips of symptomatic consecutively selected patients with hip pain (mean age 20 years (SD 6), 60% (n = 25) females) on preoperative CT scans using different measurement methods: Lee et al, Reikerås et al, Tomczak et al, and Murphy et al. Neck-shaft angle (NSA) and α angle were measured on coronal and
Aims. Assessment of bone mineral density (BMD) with dual-energy X-ray absorptiometry (DXA) is a well-established clinical technique, but it is not available in the acute trauma setting. Thus, it cannot provide a preoperative estimation of BMD to help guide the technique of fracture fixation. Alternative methods that have been suggested for assessing BMD include: 1) cortical measures, such as cortical ratios and combined cortical scores; and 2) aluminium grading systems from preoperative digital radiographs. However, limited research has been performed in this area to validate the different methods. The aim of this study was to investigate the evaluation of BMD from digital radiographs by comparing various methods against DXA scanning. Methods. A total of 54 patients with distal
Executing an extended retinacular flap containing the blood supply for the femoral head, reduction osteotomy (FHO) can be performed, increasing the potential of correction of complex hip morphologies. The aim of this study was to analyse the safety of the procedure and report the clinical and radiographic results in skeletally mature patients with a minimum follow up of two years. Twelve symptomatic patients (12 hips) with a mean age of 17 years underwent FHO using surgical hip dislocation and an extended soft tissue flap. Radiographs and magnetic resonance imaging producing
Background. Cam morphology develops during adolescence and predisposes individuals to future hip pain and osteoarthritis. An improved understanding of cam development is required to determine whether the process is modifiable. Hypothesis/Purpose. The aim of this study was to characterise the risk factors, timing, and pathogenesis of cam formation. Study Design. Longitudinal prospective observational cohort study. Methods. Longitudinal observational cohort study over three years of individuals from football club academies and an age-matched control population, aged 9–18 years at baseline. Assessments include questionnaires, clinical examination, and MRI of both hips. Alpha angle and epiphyseal extension were measured on
Periprosthetic fracture and implant loosening are two of the major reasons for revision surgery of cementless implants. Optimal implant fixation with minimal bone damage is challenging in this procedure. This pilot study investigates whether vibratory implant insertion is gentler compared to consecutive single blows for acetabular component implantation in a surrogate polyurethane (PU) model. Acetabular components (cups) were implanted into 1 mm nominal under-sized cavities in PU foams (15 and 30 per cubic foot (PCF)) using a vibratory implant insertion device and an automated impaction device for single blows. The impaction force, remaining polar gap, and lever-out moment were measured and compared between the impaction methods.Aims
Methods
Lateral femoral cutaneous nerve (LFCN) injury is a potential complication after the direct anterior approach for total hip arthroplasty (DAA-THA). The aim of this study was to determine how the location of the fasciotomy in DAA-THA affects LFCN injury. In this trial, 134 patients were randomized into a lateral fasciotomy (n = 67) or a conventional fasciotomy (n = 67) group. This study was a dual-centre, double-blind, prospective randomized controlled two-arm trial with parallel group design and a 1:1 allocation ratio. The primary endpoint was the presence of LFCN injury, which was determined by the presence of numbness, decreased sensation, tingling, jolt-like sensation, or pain over the lateral aspect of the thigh, excluding the surgical scar, using a patient-based questionnaire. The secondary endpoints were patient-reported outcome measures (PROMs) using the Western Ontario and McMaster Universities osteoarthritis index (WOMAC), Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ), and the Forgotten Joint Score-12 (FJS-12). Assessments were obtained three months after surgery.Aims
Methods
Hip resurfacing remains a potentially valuable surgical procedure for appropriately-selected patients with optimised implant choices. However, concern regarding high early failure rates continues to undermine confidence in use. A large contributor to failure is adverse local tissue reactions around metal-on-metal (MoM) bearing surfaces. Such phenomena have been well-explored around MoM total hip arthroplasties, but comparable data in equivalent hip resurfacing procedures is lacking. In order to define genetic predisposition, we performed a case-control study investigating the role of human leucocyte antigen (HLA) genotype in the development of pseudotumours around MoM hip resurfacings. A matched case-control study was performed using the prospectively-collected database at the host institution. In all, 16 MoM hip resurfacing 'cases' were identified as having symptomatic periprosthetic pseudotumours on preoperative metal artefact reduction sequence (MARS) MRI, and were subsequently histologically confirmed as high-grade aseptic lymphocyte-dominated vasculitis-associated lesions (ALVALs) at revision surgery. ‘Controls’ were matched by implant type in the absence of evidence of pseudotumour. Blood samples from all cases and controls were collected prospectively for high resolution genetic a nalysis targeting 11 separate HLA loci. Statistical significance was set at 0.10 a priori to determine the association between HLA genotype and pseudotumour formation, given the small sample size.Aims
Methods
Our objective was describing an algorithm to identify and prevent vascular injury in patients with intrapelvic components. Patients were defined as at risk to vascular injuries when components or cement migrated 5 mm or more beyond the ilioischial line in any of the pelvic incidences (anteroposterior and Judet view). In those patients, a serial investigation was initiated by a CT angiography, followed by a vascular surgeon evaluation. The investigation proceeded if necessary. The main goal was to assure a safe tissue plane between the hardware and the vessels.Aims
Methods
Objectives. Favourable results for collarless polished tapered stems have been reported, and cement creep due to taper slip may be a contributing factor. However, the ideal cement thickness around polished stems remains unknown. We investigated the influence of cement thickness on stem subsidence and cement creep. Methods. We cemented six collarless polished tapered (CPT) stems (two stems each of small, medium and large sizes) into composite femurs that had been reamed with a large CPT rasp to achieve various thicknesses of the cement mantle. Two or three tantalum balls were implanted in the proximal cement in each femur. A cyclic loading test was then performed for each stem. The migration of the balls was measured three-dimensionally, using a micro-computed tomography (CT) scanner, before and after loading. A digital displacement gauge was positioned at the stem shoulder, and stem subsidence was measured continuously by the gauge. Final stem subsidence was measured at the balls at the end of each stem. Results. A strong positive correlation was observed between mean cement thickness and stem subsidence in the CT slices on the balls. In the small stems, the balls moved downward to almost the same extent as the stem. There was a significant negative correlation between cement thickness and the horizontal:downward ratio of ball movement. Conclusion. Collarless polished tapered stems with thicker cement mantles resulted in greater subsidence of both stem and cement. This suggests that excessive thickness of the cement mantle may interfere with effective
The frequency of severe femoral retroversion is unclear in patients with femoroacetabular impingement (FAI). This study aimed to investigate mean femoral version (FV), the frequency of absolute femoral retroversion, and the combination of decreased FV and acetabular retroversion (AR) in symptomatic patients with FAI subtypes. A retrospective institutional review board-approved observational study was performed with 333 symptomatic patients (384 hips) with hip pain due to FAI evaluated for hip preservation surgery. Overall, 142 patients (165 hips) had cam-type FAI, while 118 patients (137 hips) had mixed-type FAI. The allocation to each subgroup was based on reference values calculated on anteroposterior radiographs. CT/MRI-based measurement of FV (Murphy method) and AV were retrospectively compared among five FAI subgroups. Frequency of decreased FV < 10°, severely decreased FV < 5°, and absolute femoral retroversion (FV < 0°) was analyzed.Aims
Methods
Introduction. Acetabular and spino-pelvic (SP) morphological parameters are important determinants of hip joint dynamics. This study aims to determine whether acetabular and SP morphological differences exist between hips with and without cam morphology and between symptomatic and asymptomatic hips with cam morphology. Patients/Materials & Methods. A prospective cohort of 67 patients/hips was studied. Hips were either asymptomatic with no cam (Controls, n=18), symptomatic with cam (n=26) or asymptomatic with cam (n=23). CT-based quantitative assessments of femoral, acetabular, pelvic and spino-pelvic parameters were performed. Measurements were compared between controls and those with a cam deformity, as well as between the 3 groups. Morphological parameters that were independent predictors of a symptomatic Cam were determined using a regression analysis. Results. Hips with cam deformity had slightly smaller subtended angles superior-anteriorly (87° Vs 84°, p=0.04) and greater pelvic incidence (53° Vs 48°, p=0.003) compared to controls. Symptomatic Cams had greater acetabular version (p<0.01), greater subtended angles superiorly and superior-posteriorly (p=0.01), higher pelvic incidence (p=0.02), greater alpha angles and lower femoral neck-shaft angles compared to asymptomatic cams (p<0.01) and controls (p<0.01). The four predictors of symptomatic cam included antero-superior alpha angle, femoral neck-shaft angle, acetabular depth and pelvic incidence. Discussion. Symptomatic hips had a greater amount of supero-posterior coverage; which would be the contact area between a
Rotational acetabular osteotomy (RAO) has been reported to be effective in improving symptoms and preventing osteoarthritis (OA) progression in patients with mild to severe develomental dysplasia of the hip (DDH). However, some patients develop secondary OA even when the preoperative joint space is normal; determining who will progress to OA is difficult. We evaluated whether the preoperative cartilage condition may predict OA progression following surgery using T2 mapping MRI. We reviewed 61 hips with early-stage OA in 61 patients who underwent RAO for DDH. They underwent preoperative and five-year postoperative radiological analysis of the hip. Those with a joint space narrowing of more than 1 mm were considered to have 'OA progression'. Preoperative assessment of articular cartilage was also performed using 3T MRI with the T2 mapping technique. The region of interest was defined as the weightbearing portion of the acetabulum and femoral head.Aims
Methods
The direct anterior approach (DAA) for total hip arthroplasty (THA) has potential advantages over other approaches and is most commonly performed with the patient in the supine position. We describe a technique for DAA THA with the patient in the lateral decubitus position and report the early clinical and radiological outcomes, the characteristics of the learning curve, and perioperative complications. All primary DAA THAs performed in the lateral position by a single surgeon over a four-year period from the surgeon’s first case using the technique were identified from a prospectively collected database. Modified Harris Hip Scores (mHHS) were collected to assess clinical outcome, and routine radiological analysis was performed. Retrospective review of the medical records identified perioperative complications, the characteristics of the learning curve, and revisions.Aims
Methods
The prevalence of combined abnormalities of femoral torsion (FT) and tibial torsion (TT) is unknown in patients with femoroacetabular impingement (FAI) and hip dysplasia. This study aimed to determine the prevalence of combined abnormalities of FT and TT, and which subgroups are associated with combined abnormalities of FT and TT. We retrospectively evaluated symptomatic patients with FAI or hip dysplasia with CT scans performed between September 2011 and September 2016. A total of 261 hips (174 patients) had a measurement of FT and TT. Their mean age was 31 years (SD 9), and 63% were female (165 hips). Patients were compared to an asymptomatic control group (48 hips, 27 patients) who had CT scans including femur and tibia available for analysis, which had been acquired for nonorthopaedic reasons. Comparisons were conducted using analysis of variance with Bonferroni correction.Aims
Methods
To compare the in vivo long-term fixation achieved by two acetabular components with different porous ingrowth surfaces using radiostereometric analysis (RSA). This was a minimum ten-year follow-up of a prospective randomized trial of 62 hips with two different porous ingrowth acetabular components. RSA exams had previously been acquired through two years of follow-up. Patients returned for RSA examination at a minimum of ten years. In addition, radiological appearance of these acetabular components was analyzed, and patient-reported outcome measures (PROMs) obtained.Aims
Methods
The aim of this study was to develop a novel computational model for estimating head/stem taper mechanics during different simulated assembly conditions. Finite element models of generic cobalt-chromium (CoCr) heads on a titanium stem taper were developed and driven using dynamic assembly loads collected from clinicians. To verify contact mechanics at the taper interface, comparisons of deformed microgroove characteristics (height and width of microgrooves) were made between model estimates with those measured from five retrieved implants. Additionally, these models were used to assess the role of assembly technique—one-hit versus three-hits—on the taper interlock mechanical behaviour.Aims
Methods
Cementless acetabular components rely on press-fit fixation for initial stability. In certain cases, initial stability is more difficult to obtain (such as during revision). No current study evaluates how a surgeon’s impaction technique (mallet mass, mallet velocity, and number of strikes) may affect component fixation. This study seeks to answer the following research questions: 1) how does impaction technique affect a) bone strain generation and deterioration (and hence implant stability) and b) seating in different density bones?; and 2) can an impaction technique be recommended to minimize risk of implant loosening while ensuring seating of the acetabular component? A custom drop tower was used to simulate surgical strikes seating acetabular components into synthetic bone. Strike velocity and drop mass were varied. Synthetic bone strain was measured using strain gauges and stability was assessed via push-out tests. Polar gap was measured using optical trackers.Aims
Methods
We present the long-term results of simple varus intertrochanteric osteotomy for osteonecrosis of the femoral head. We followed 26 hips in 20 patients, with a mean age at the time of surgery of 36 years, for a mean of 12.5 years. The mean varus angulation was 23°. The outcome in 19 of the hips (73%) was good or excellent; seven (27%) had a fair or poor result, with four needing some form of prosthetic arthroplasty. Simple varus intertrochanteric osteotomy is indicated, even if the extent of the capital infarct comprises more than 50% of the diameter of maximum
