Publications by authors named "Armando Hoch"

Hip abductors are essential for hip function. To understand abduction weakness, it is important to know which muscles contribute to abduction force. Our aim was to investigate the effects of an experimentally induced weakness of the different muscles (tensor fasciae latae [TFL], gluteus medius and minimus (Gmed/min), gluteus maximus [Gmax]) on the abduction force.

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Background: Total Hip Arthroplasty (THA) is a well-established and common orthopedic surgery. Due to the complexity involved in THA, orthopedic surgeons require rigorous training. However, the current gold standard, the tutor-guided and -evaluated apprenticeship model is time-consuming, costly, and poses risks to patients.

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Background: This experimental study aimed at directly comparing conventional and endoscopic-assisted curettage towards (1) amount of residual tumour tissue (RTT) and (2) differences between techniques regarding surgical time and surgeons' experience level.

Methods: Three orthopaedic surgeons (trainee, consultant, senior consultant) performed both conventional (4x each) and endoscopic-assisted curettages (4x each) on specifically prepared cortical-soft cancellous femur and tibia sawbone models. "Tumours" consisted of radio-opaque polyurethane-based foam injected into prepared holes.

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Background: Previous studies have shown that dexamethasone has a positive effect on postoperative pain control, opioid consumption, nausea, and vomiting and length of hospital stay after arthroplasty surgery.

Purpose/hypothesis: The purpose of this study was to assess whether adding perioperative dexamethasone to our current pain regimen after hip arthroscopy is more effective than a placebo. It was hypothesized that dexamethasone would reduce postoperative pain, reduce opioid consumption, improve subjective pain and nausea scores, and reduce the number of vomiting events.

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Article Synopsis
  • - This study investigates how high femoral offset (hFO) combinations in primary cementless total hip arthroplasty (THA) may contribute to aseptic femoral loosening, focusing on the effects of lateralized stems and large femoral head lengths.
  • - A cohort of 2,459 THA patients was analyzed, revealing that 0.6% had aseptic loosening, with a significant presence of hFO combinations in the loosening group compared to the non-loosening group.
  • - Results indicate that hFO combinations significantly increase the risk of aseptic loosening (3.7 times higher probability), suggesting a need for adjustments in postoperative protocols to promote proper stem ingrowth.
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  • Early aseptic loosening in uncemented total hip arthroplasty (THA) is primarily caused by inadequate integration of the femoral stem, often due to excessive micromotions.
  • The study investigated how factors like higher femoral offset, smaller stem sizes, and obesity contribute to these micromotions, using finite element analysis on CT scans of patients.
  • Results indicated that combinations of lower femoral offset, larger body weight, and smaller stem sizes significantly increased micromotion, posing a risk for improper osseointegration in patients undergoing THA.
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  • The study focuses on enhancing the periacetabular osteotomy (PAO) procedure using augmented reality (AR) to improve the placement and orientation of bone structures.
  • Researchers conducted a cadaveric study on 14 hip specimens to assess the feasibility and accuracy of AR guidance in executing this complex surgical technique.
  • Results indicated that the AR-guided approach allows for effective corrections in surgical planning, with minimal errors, suggesting it could be a promising tool for future surgeries.
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In clinical practice, image-based postoperative evaluation is still performed without state-of-the-art computer methods, as these are not sufficiently automated. In this study we propose a fully automatic 3D postoperative outcome quantification method for the relevant steps of orthopaedic interventions on the example of Periacetabular Osteotomy of Ganz (PAO). A typical orthopaedic intervention involves cutting bone, anatomy manipulation and repositioning as well as implant placement.

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Introduction: Chronic hip abductor insufficiency is a rare debilitating condition. In cases refractory to conservative treatment and not amenable to direct repair an augmentation becomes necessary. The preferred salvage method at our institution is augmentation with the anterior third of the gluteus maximus tendon.

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Squatting is a common daily activity and fundamental exercise in resistance training and closed kinetic chain programs. The aim of this study was to investigate the effects of an experimentally induced weakness of the gluteal muscles on joint kinematics, reactions forces (JRFs), and dynamic balance performance during deep bilateral squats in healthy young adults. Ten healthy adults received sequential blocks of (1) branch of the superior gluteal nerve to the tensor fasciae latae (SGNtfl) muscle, (2) superior gluteal nerve (SGN), and (3) inferior gluteal nerve (IGN) on the dominant right leg.

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Patients older than 40 years with a body-mass-index (BMI) >30 kg/m , a femoroacetabular-impingement (FAI) and little cartilage damage are a challenge for hip surgeons. Hip-arthroscopy (HAS) or conservative therapy until a total hip arthroplasty (THA) is needed are possible treatments. Our research purpose was to compare the clinical results and complication/reoperation rate after HAS and THA in patients with obesity over 40 years.

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Background: The relationship between functional femoral antetorsion, the greater trochanter (GT) position and anatomical antetorsion has been demonstrated in patients with a primary hip pathology. However, the functional antetorsion and GT position have not been analyzed in patellofemoral dysplastic knees. The aim of this study was to develop a three-dimensional (3D) measurement to quantify the functional femoral antetorsion and position of the GT and to analyze these measurements in a cohort of high-grade patellofemoral dysplastic knees.

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Article Synopsis
  • This study analyzed the outcomes of total hip arthroplasty (THA) in patients with Legg-Calvé-Perthes disease (LCPD) using two surgical methods: the direct anterior approach (DAA) and non-anterior approaches.
  • The research included patients who underwent THA between 2004 and 2018, comparing their post-surgery hip function and complication rates over an average follow-up period of around 8 years.
  • Results indicated that the DAA led to comparable hip function and complication rates to non-anterior approaches, suggesting it could be a viable surgical option for LCPD sequelae.
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Background: Inaccurately scaled radiographs for total hip arthroplasty (THA) templating are a source of error not recognizable to the surgeon and may lead to inaccurate reconstruction and thus revision surgery or litigation. Planning based on computed tomography (CT) scans is more accurate but associated with higher radiation exposure. The aim of this study was (1) to retrospectively assess the scaling deviation of pelvic radiographs; (2) to prospectively assess the feasibility and the radiation dose of THA templating on radiograph-like images reconstructed from a tin-filtered ultra-low-dose CT dataset.

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Background: Computer-assisted techniques for surgical treatment of femoral deformities have become increasingly important. In state-of-the-art 3D deformity assessments, the contralateral side is used as template for correction as it commonly represents normal anatomy. Contributing to this, an iterative closest point (ICP) algorithm is used for registration.

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  • The study investigates the relationship between pelvic tilt and leg alignment, focusing on how pelvic tilt correlates with frontal (hip-knee-ankle angle) and axial (femoral and tibial torsion) leg alignment in healthy individuals.
  • A total of 30 healthy subjects were analyzed using biplanar long leg radiographs, and results showed significant correlations between pelvic tilt and both knee valgus and tibial torsion, with posterior metrics indicating a moderate predictive power of these factors on pelvic tilt.
  • The findings suggest a weak correlation between valgus alignment, tibial torsion, and anterior pelvic tilt, highlighting the need to consider these interrelations in patients with joint issues affecting the hip, knee, and spine.
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  • The study aimed to determine how excessive femoral torsion (FT) affects the outcomes of total knee arthroplasty (TKA) and its relationship with anterior knee pain, focusing on preoperative patellofemoral alignment.
  • Researchers compared two groups of TKA patients: one with excessive FT (>20°) and one with normal FT (<20°), analyzing clinical scores and radiographic parameters two years post-surgery.
  • Results showed no significant differences in clinical outcomes or radiographic parameters between the two groups, indicating that correcting leg axis deformities during TKA may mitigate issues linked to excessive FT.
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Purpose: High-grade patellofemoral dysplasia is often associated with concomitant axial and frontal leg malalignment. However, curvature of the femur and sagittal flexion of the trochlea has not yet been studied in patellofemoral dysplastic knees. The aim of the study was to quantify the femoral curvature and sagittal flexion of the trochlea in both high-grade patellofemoral dysplastic and healthy knees.

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Background: The anteroposterior (ap) radiograph of the pelvis is decisive in the diagnosis of different pathologies of the hip joint. Technical advantages have reduced the radiation dose of pelvic CT to levels comparable to radiographs. The purpose of this study was to validate if standard radiographic parameters (lateral center edge angle, medial center edge angle, acetabular index, acetabular arc, extrusion index, crossover sign and posterior wall sign) can accurately be determined on radiograph-like projections reconstructed from the CT dataset pre- and postoperatively.

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Background: Malcorrection of the acetabular fragment in periacetabular osteotomy (PAO) is associated with inferior outcomes. 2-dimensional radiographic parameters are being used for intraoperative verification of a satisfactory result. After reorientation of the fragment, the acetabular version must be verified with an intraoperative radiograph.

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Background: There is a trend toward minimally invasive and more automated procedures in orthopedic surgery. An important aspect in the further development of these techniques is the quantitative assessment of the surgical approach. The aim of this scoping review is to deliver a structured overview on the currently used methods for quantitative analysis of a surgical approaches' invasiveness in orthopedic procedures.

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Background: AR based navigation of spine surgeries may not only provide accurate surgical execution but also operator independency by compensating for potential skill deficits. "Direct" AR-navigation, namely superposing trajectories on anatomy directly, have not been investigated regarding their accuracy and operator's dependence.Purpose of this study was to prove operator independent reliability and accuracy of both AR assisted pedicle screw navigation and AR assisted rod bending in a cadaver setting.

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The instrumentation of spinal fusion surgeries includes pedicle screw placement and rod implantation. While several surgical navigation approaches have been proposed for pedicle screw placement, less attention has been devoted towards the guidance of patient-specific adaptation of the rod implant. We propose a marker-free and intuitive Augmented Reality (AR) approach to navigate the bending process required for rod implantation.

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