Biomechanical Analysis of a Novel Acetabulum Reconstruction Technique with Acetabulum Reconstruction Cage and Threaded Rods after Type II Pelvic Resections

Background. Periacetabular resections with reconstruction has high rates of complications due to the complexity of the reconstruction. We have improvised a novel technique of reconstruction for type II and type II + III pelvic resections with the use of a commercially available acetabulum reconstruction cage (gap II, Stryker) and threaded rods.Objectives. The aim of our study is to determine the biomechanical strength of our reconstruction compared to the traditional cemented total hip replacement (THR) designs in normal acetabulum and establish its mode of failure.Methods. Five sets of hemipelvises were biomechanically tested (Instron® 3848, MA, USA). These constructs were subjected to cyclic loading and load to failure.Results. The reconstructed acetabulum was stiffer and required a higher load to failure compared to the intact pelvis with a standard THR. The mean stiffness of the reconstructed pelvis was1738.6±200.3 Nmm−1compared to the intact pelvis, which was911.4±172.7 Nmm−1(Pvalue = 0.01). The mean load to failure for the standard acetabular cup construct was3297.3±117.7 N while that of the reconstructed pelvis with the acetabulum cage and threaded rods was4863.8±7.0 N.Conclusion. Reconstruction of the pelvis with an acetabular reconstruction cage and threaded rods is a biomechanical viable option.

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Mid-term result of acetabular reconstruction using a Kerboull-type acetabular reinforcement device with hydroxyapatite impaction

Journal of Orthopaedics Trauma and Rehabilitation ◽

10.1177/2210491720971838 ◽

2020 ◽

pp. 221049172097183

Author(s):

Hidetatsu Tanaka ◽

Daisuke Chiba ◽

Norikazu Yamada ◽

Masahiko Tanaka ◽

Yoshiyuki Kuwahara ◽

...

Keyword(s):

Survival Rates ◽

Acetabular Reconstruction ◽

Type Ii ◽

Term Result ◽

Acetabular Bone ◽

Kaplan Meier ◽

Acetabular Bone Defects ◽

The Mean ◽

Mid Term Results ◽

Reinforcement Device

The aim of this study is to investigate the mid-term results of 29 hips in 26 patients who underwent acetabular reconstruction using a Kerboull-type acetabular reinforcement device and impaction with hydroxyapatite (HA) granules. The acetabular bone defects were AAOS type II for six hips and type III for 23 hips. The mean Merle d’Aubigné clinical scores were significantly improved after operation. Six hips developed implant migration and breakage, and five of six hips were revised after an average of 5.5 (range 2.0–8.8) years. All hips with thickness of the grafted HA less than 10 mm were stable. As the HA became thicker, the failure rate were significantly increased. The Kaplan–Meier survival rates at 10 years were 73.2%, with 100% and 67.0% for AAOS type II and III defect respectively as the end point was failure condition. Reconstruction using a Kerboull-type acetabular reinforcement device and impaction with HA granules was an alternative method in the absence of adequate allografts.

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Anatomical and Biomechanical properties of MPFL reconstruction technique using Adductor Magnus tendon graft

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967120s00315 ◽

2020 ◽

Vol 8 (5_suppl4) ◽

pp. 2325967120S0031

Author(s):

Danko Dan Milinkovic ◽

Christian Fink ◽

Petri Sillanpää ◽

Michael J. Raschke ◽

Christoph Kittl ◽

...

Keyword(s):

Insertion Site ◽

Biomechanical Properties ◽

Tendon Graft ◽

Mpfl Reconstruction ◽

Reconstruction Technique ◽

Maximum Elongation ◽

Load To Failure ◽

Application Potential ◽

Length Changes ◽

The Mean

Aims and Objectives: The main goal of the presented study was to evaluate the anatomical and biomechanical properties of the proposed surgical technique for anatomical Medial Patellofemoral ligament (MPFL) reconstruction using the flat Adductor tendon (AT) graft in order to primarily determine its overall plausibility and application potential, as well as to reveal the main risks and pitfalls of the technique. Materials and Methods: Anatomical descriptive evaluation, followed by biomechanical testing of the proposed AT- MPFL reconstruction was conducted on 12 fresh frozen human cadaveric knees. The morphological and topographical features of the AT and native MPFL were reported. The biomechanical tests were performed in order to determine the strength and resistance to maximum loading force of the reconstruction. The construct was placed in an uniaxial testing machine and cyclically loaded 500 times between 5 and 50N, followed by load to failure, measuring the maximum elongation, stiffness and maximum load respectively. Results: Regarding the anatomical evaluation of the structures in focus, several findings have been reported. The mean length of the tendon was found to be 12,59±1,54cm, the mean distance between the insertion on the Adductor tubercule and Hiatus was measured at 10,83±1,27cm, exceeding the mean desired length of the graft, found at 7,54±0,45cm by 2,43±0,56cm. The desired length of the graft was based on the measured length of the native MPFL with additional ±25-30mm of the tendon that allows for intraoperative length changes and different means of patellar fixation depending on the surgeons preference. The insertion of the Adductor tendon on the Adductor tubercule was found to be superior and posterior to the insertion of the native MPFL. The distal portion of AT was found to be consisted of two distinct parts with varying fiber orientation, the tendinous and the membranous part. After cyclic load, the maximum elongation was reported at 1,9 ± 0,4mm. The mean stiffness and load to failure of the construct were measured at 26,2±7,6N/mm and 148,74±22,01N. The graft failed at the patellar insertion site in two of the tested specimens and at the femoral insertion site in the remaining 10. Conclusion: Due to its advantageous anatomical and topographical aspects, as well as adequate biomechanical properties, the Adductor tendon graft caries a high utilization potential for MPFL reconstruction. Application that allows for primarily soft tissue fixation on the patella, in addition to absence of femoral drill holes with consequently no risk of injury to the physis, makes the AT graft choice a preferable option when considering MPFL reconstruction in patients with open growth plates. Even though it includes graft and methods of fixation alternative to the traditionally used techniques, this reconstruction is not exclusively predetermined for the skeletally immature patients and has a high application potential for the older patient population as well.

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The fate of femoral head autograft in acetabular reconstruction in dysplastic hips at midterm

Journal of Orthopaedic Surgery ◽

10.1177/2309499020957109 ◽

2020 ◽

Vol 28 (3) ◽

pp. 230949902095710

Author(s):

Arif Jan Hamrayev ◽

Mehmet Ozbey Buyukkuscu ◽

Abdulhamit Misir ◽

Sukru Sarper Gursu

Keyword(s):

Femoral Head ◽

Acetabular Component ◽

Hip Dislocation ◽

Hip Osteoarthritis ◽

Acetabular Reconstruction ◽

Acetabular Coverage ◽

Acetabular Cup ◽

Developmental Hip Dysplasia ◽

The Mean

Purpose: To evaluate the acetabular cup and graft survival in patients who underwent total hip arthroplasty (THA) with the diagnosis of dysplastic hip osteoarthritis and received a femoral head autograft due to acetabular coverage deficiency. Methods: Between January 2005 and December 2016, 83 hip prostheses of 80 patients who underwent THA using femoral head autografts and were followed up for at least 2 years were retrospectively evaluated. Seventy-four hips of the remaining 71 patients (57 female (80%)) were included. Mean patient age at surgery was 51 ± 16 (range 18–76) years. The mean follow-up duration was 76 ± 25 (range 25–161) months. Acetabular inclination and graft thickness, contact length, percentage of coverage, and graft resorption were examined on postoperative and final follow-up radiographs. The presence of a radiolucent area around the acetabular and femoral components indicating loosening was also evaluated. Results: The mean postoperative acetabular component inclination was 44 ± 5.1° (range 30–48°) with mean graft coverage of 34 ± 4.8% (range 24–46%). In all patients, autograft union with the pelvis was seen and the lateral overflow was remodeled. Fifteen patients (20%) underwent revision surgery due to aseptic acetabular component loosening in four, nontraumatic recurrent dislocations in eight, periprosthetic infection in one, acetabular component protrusion in one, and traumatic hip dislocation in one. Conclusion: In patients with osteoarthritis secondary to developmental hip dysplasia, the use of femoral head autografts to eliminate acetabular coverage deficiency during THA achieves acceptable midterm postoperative radiological outcomes. Increased acetabular bone stock may be beneficial in possible future revision surgeries.

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The accuracy of free-hand cup positioning: a CT based measurement in a South Indian hospital

International Journal of Research in Orthopaedics ◽

10.18203/issn.2455-4510.intjresorthop20184380 ◽

2018 ◽

Vol 4 (6) ◽

pp. 887

Author(s):

Vetrivel Chezian Sengodan ◽

S. Marimuthu ◽

Raghupathy Ramasamy

Keyword(s):

Total Hip Arthroplasty ◽

Ct Scan ◽

Hip Arthroplasty ◽

Acetabular Reconstruction ◽

Acetabular Cup ◽

Acetabular Version ◽

Total Hip ◽

South Indian ◽

The Mean ◽

Free Hand Technique

Background: In total hip arthroplasty, the restoration of normal hip center in acetabular reconstruction encourages the normal bio mechanics. The impingement, dislocation, and implant wear have increased the interest in accurate component placement in arthroplasty. This study is to determine the accuracy of the free hand technique in the acetabular cup placement in relation to native acetabulam using CT scan images.Methods: This study was done in the Coimbatore Medical College and Hospital from June 2015 to March 2016. Twenty patients who have undergone total hip replacements were subjected to CT scan of pelvis preoperatively and postoperatively. The acetabular cup version and the inclination were measured and analyzed statistically.Results: The mean acetabular version was 17.5◦±6.5◦ and the inclination was 46.6◦±9.3◦ pre operatively. Post operatively the mean acetabular version was 26.3◦±17.3◦ and the inclination was 41.7◦±10.9◦. With reference to the component version it ranged from 12.5˚ of retroversion to 62.5˚ anteversion with a mean of 26.3◦±17.3◦. The component inclination ranged from 15.6◦ to 58.4◦ with a mean of 41.7◦±10.9◦. On combining component version and inclination, only (50%) was within the safe zone.Conclusions: Based on the CT finding acetabular version and inclination differs from individual to individual. During acetabular cup placement in total hip arthroplasty using free hand technique, our study shows that that inclination is better achieved and the anteversion is over targeted in most of the cases.

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The global dynamics of stochastic Holling type II predator-prey models with non constant mortality rate

Filomat ◽

10.2298/fil1718811z ◽

2017 ◽

Vol 31 (18) ◽

pp. 5811-5825

Author(s):

Xinhong Zhang

Keyword(s):

Mortality Rate ◽

Stochastic Model ◽

Sufficient Conditions ◽

Positive Periodic Solution ◽

Global Dynamics ◽

Type Ii ◽

Predator Prey ◽

Persistence In The Mean ◽

The Mean ◽

Predator Prey Models

In this paper we study the global dynamics of stochastic predator-prey models with non constant mortality rate and Holling type II response. Concretely, we establish sufficient conditions for the extinction and persistence in the mean of autonomous stochastic model and obtain a critical value between them. Then by constructing appropriate Lyapunov functions, we prove that there is a nontrivial positive periodic solution to the non-autonomous stochastic model. Finally, numerical examples are introduced to illustrate the results developed.

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Flow cytometric identification and isolation of hypertrophic type II pneumocytes after partial pneumonectomy

AJP Cell Physiology ◽

10.1152/ajpcell.1989.257.3.c528 ◽

1989 ◽

Vol 257 (3) ◽

pp. C528-C536 ◽

Cited By ~ 46

Author(s):

B. D. Uhal ◽

S. R. Rannels ◽

D. E. Rannels

Keyword(s):

Gradient Centrifugation ◽

Type Ii Cells ◽

Type Ii ◽

Acridine Orange Staining ◽

Flow Cytometric ◽

Percoll Density Gradient Centrifugation ◽

Type Ii Pneumocytes ◽

The Mean ◽

Cellular Dna ◽

The Right

Type II pneumocytes were isolated by either Percoll density gradient centrifugation or by immunoglobulin G (IgG) panning from the lungs of normal rats and the right lung of rats subjected to left pneumonectomy. Cells were studied at 7- (pnx-7) and 15- (pnx-15) days postoperative, times during and after, respectively, rapid compensatory growth of the right lung. Acridine orange staining permitted resolution of type II cells from contaminants on the basis of high red fluorescence (greater than 590 nm). Simultaneous measurement of forward-angle light scatter (FALS) suggested a shift of pnx-7 cells toward greater size, which was reversed in pnx-15 cells. By Percoll gradient isolation, approximately 15% of pnx-7 cells analyzed were above the mean FALS of control cells. In contrast, approximately 30% of the pnx-7 cells isolated by IgG panning were above the mean FALS of corresponding control cells. Biochemical analyses of pnx-7 cells separated by cell sorting into "high FALS" and "low FALS" subgroups revealed that high FALS type II cells contained 50% more protein (P less than 0.05) and 140% more RNA (P less than 0.01) than low FALS cells, with no significant change in cellular DNA content. These data are consistent with previous studies of type II cells isolated from the lungs of pneumonectomized animals and confirm the presence of hypertrophic cells in these preparations. They provide a foundation from which to design further flow cytometric studies of the role of hypertrophic type II pneumocytes in compensatory lung growth.

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MDCT-Based Finite Element Analyses: Are Measurements at the Lumbar Spine Associated with the Biomechanical Strength of Functional Spinal Units of Incidental Osteoporotic Fractures along the Thoracolumbar Spine?

Diagnostics ◽

10.3390/diagnostics11030455 ◽

2021 ◽

Vol 11 (3) ◽

pp. 455

Author(s):

Nico Sollmann ◽

Nithin Manohar Rayudu ◽

Long Yu Yeung ◽

Anjany Sekuboyina ◽

Egon Burian ◽

...

Keyword(s):

Finite Element ◽

Lumbar Spine ◽

Fracture Risk ◽

Thoracolumbar Spine ◽

Areal Bone Mineral Density ◽

Mineral Density ◽

Osteoporotic Vertebral Fractures ◽

The Mean ◽

Biomechanical Strength

Assessment of osteoporosis-associated fracture risk during clinical routine is based on the evaluation of clinical risk factors and T-scores, as derived from measurements of areal bone mineral density (aBMD). However, these parameters are limited in their ability to identify patients at high fracture risk. Finite element models (FEMs) have shown to improve bone strength prediction beyond aBMD. This study aims to investigate whether FEM measurements at the lumbar spine can predict the biomechanical strength of functional spinal units (FSUs) with incidental osteoporotic vertebral fractures (VFs) along the thoracolumbar spine. Multi-detector computed tomography (MDCT) data of 11 patients (5 females and 6 males, median age: 67 years) who underwent MDCT twice (median interval between baseline and follow-up MDCT: 18 months) and sustained an incidental osteoporotic VF between baseline and follow-up scanning were used. Based on baseline MDCT data, two FSUs consisting of vertebral bodies and intervertebral discs (IVDs) were modeled: one standardly capturing L1-IVD–L2-IVD–L3 (FSU_L1–L3) and one modeling the incidentally fractured vertebral body at the center of the FSU (FSU_F). Furthermore, volumetric BMD (vBMD) derived from MDCT, FEM-based displacement, and FEM-based load of the single vertebrae L1 to L3 were determined. Statistically significant correlations (adjusted for a BMD ratio of fracture/L1–L3 segments) were revealed between the FSU_F and mean load of L1 to L3 (r = 0.814, p = 0.004) and the mean vBMD of L1 to L3 (r = 0.745, p = 0.013), whereas there was no statistically significant association between the FSU_F and FSU_L1–L3 or between FSU_F and the mean displacement of L1 to L3 (p > 0.05). In conclusion, FEM measurements of single vertebrae at the lumbar spine may be able to predict the biomechanical strength of incidentally fractured vertebral segments along the thoracolumbar spine, while FSUs seem to predict only segment-specific fracture risk.

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Interference Screw Versus Suture Anchors for Femoral Fixation in Medial Patellofemoral Ligament Reconstruction: A Biomechanical Study

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967121989282 ◽

2021 ◽

Vol 9 (3) ◽

pp. 232596712198928

Author(s):

Heath P. Gould ◽

Nicholas R. Delaney ◽

Brent G. Parks ◽

Roshan T. Melvani ◽

Richard Y. Hinton

Keyword(s):

Medial Patellofemoral Ligament ◽

Interference Screw ◽

Biomechanical Study ◽

Graft Fixation ◽

Mpfl Reconstruction ◽

Suture Anchors ◽

Femoral Fixation ◽

Significant Difference ◽

Load To Failure ◽

The Mean

Background: Femoral-sided graft fixation in medial patellofemoral ligament (MPFL) reconstruction is commonly performed using an interference screw (IS). However, the IS method is associated with several clinical disadvantages that may be ameliorated by the use of suture anchors (SAs) for femoral fixation. Purpose: To compare the load to failure and stiffness of SAs versus an IS for the femoral fixation of a semitendinosus autograft in MPFL reconstruction. Study Design: Controlled laboratory study. Methods: Based on a priori power analysis, a total of 6 matched pairs of cadaveric knees were included. Specimens in each pair were randomly assigned to receive either SA or IS fixation. After an appropriate reconstruction procedure, the looped end of the MPFL graft was pulled laterally at a rate of 6 mm/s until construct failure. The best-fit slope of the load-displacement curve was then used to calculate the stiffness (N/mm) in a post hoc fashion. A paired t test was used to compare the mean load to failure and the mean stiffness between groups. Results: No significant difference in load to failure was observed between the IS and the SA fixation groups (294.0 ± 61.1 vs 250.0 ± 55.9; P = .352), although the mean stiffness was significantly higher in IS specimens (34.5 ± 9.6 vs 14.7 ± 1.2; P = .004). All IS reconstructions failed by graft pullout from the femoral tunnel, whereas 5 of the 6 SA reconstructions failed by anchor pullout. Conclusion: In this biomechanical study using a cadaveric model of MPFL reconstruction, SA femoral fixation was not significantly different from IS fixation in terms of load to failure. The mean load-to-failure values for both reconstruction techniques were greater than the literature-reported values for the native MPFL. Clinical Relevance: These results suggest that SAs are a biomechanically viable alternative for femoral-sided graft fixation in MPFL reconstruction.

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Accuracy of cup placement in total hip arthroplasty by means of a mechanical positioning device: a comprehensive cadaveric 3d analysis of 16 specimens

Hip International ◽

10.1177/1120700019874822 ◽

2019 ◽

pp. 112070001987482

Author(s):

Arthur J Kievit ◽

Johannes G G Dobbe ◽

Wouter H Mallee ◽

Leendert Blankevoort ◽

Geert J Streekstra ◽

...

Keyword(s):

3D Models ◽

Safe Zone ◽

3D Analysis ◽

Anterior Pelvic Plane ◽

Mechanical Device ◽

Acetabular Cup ◽

Anteversion Angle ◽

Positioning Device ◽

The Mean ◽

Safe Zones

Introduction: We tested whether a mechanical device (such as Hipsecure) to pinpoint the anterior pelvic plane (APP) as a guide can improve acetabular cup placement. To assess accuracy we asked: (1) is the APP an effective guide to position acetabular cup placement within acceptable ° of divergence from the optimal 40° inclination and 15° anteversion; (2) could a mechanical device increase the number of acetabular cup placements within Lewinnek’s safe zone (i.e. inclination 30° to 50°; anteversion 5° to 25°)? Methods: 16 cadaveric specimens were used to assess the 3D surgical success of using a mechanical device APP to guide acetabular cup placement along the APP. We used the Hipsecure mechanical device to implant acetabular cups at 40° inclination and 15° anteversion. Subequently, all cadaveric specimens with implants were scanned with a CT and 3D models were created of the pelvis and acetabular cups to assess the outcome in terms of Lewinnek’s safe zones. Results: The mean inclination of the 16 implants was 40.6° (95% CI, 37.7–43.4) and the mean anteversion angle was 13.4° (95% CI, 10.7–16.1). All 16 cup placements were within Lewinnek’s safe zone for inclination (between 30° and 50°) and all but 2 were within Lewinnek’s safe zone for anteversion (between 5° and 25°). Conclusion: In cadaveric specimens, the use of a mechanical device and the APP as a guide for acetabular cup placement resulted in good positioning with respect to both of Lewinnek’s safe zones.

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Minimal Invasive Surgery for Gastroesophageal Reflux Disease and Hiatus Hernia—Our Experience: A Case Series with Review of Literature

International Journal of Recent Surgical and Medical Sciences ◽

10.1055/s-0041-1731115 ◽

2021 ◽

Author(s):

Rafique Umer Harvitkar ◽

Abhijit Joshi

Keyword(s):

Retrospective Study ◽

Gastroesophageal Reflux Disease ◽

Gastroesophageal Reflux ◽

Operating Time ◽

Type I ◽

Type Ii ◽

The Mean ◽

Gerd Symptoms

Abstract Introduction Laparoscopic fundoplication (LF) has almost completely replaced the open procedure performed for gastroesophageal reflux disease (GERD) and hiatus hernia (HH). Several studies have suggested that long-term results with surgery for GERD are better than a medical line of management. In this retrospective study, we outline our experience with LF over 10 years. Also, we analyze the factors that would help us in better patient selection, thereby positively affecting the outcomes of surgery. Patients and Methods In this retrospective study, we identified 27 patients (14 females and 13 males) operated upon by a single surgeon from 2010 to 2020 at our institution. Out of these, 25 patients (12 females and 13 males) had GERD with type I HH and 2 (both females) had type II HH without GERD. The age range was 24 to 75 years. All patients had undergone oesophago-gastro-duodenoscopy (OGD scopy). A total of 25 patients had various degrees of esophagitis. Two patients had no esophagitis. These patients were analyzed for age, sex, symptoms, preoperative evaluation, exact procedure performed (Nissen’s vs. Toupet’s vs. cruroplasty + gastropexy), morbidity/mortality, and functional outcomes. They were also reviewed to examine the length of stay, length of procedure, complications, and recurrent symptoms on follow-up. Symptoms were assessed objectively with a score for six classical GERD symptoms preoperatively and on follow-up at 1-, 4- and 6-weeks postsurgery. Further evaluation was performed after 6 months and then annually for 2 years. Results 14 females (53%) and 13 males (48%) with a diagnosis of GERD (with type I HH) and type II HH were operated upon. The mean age was 46 years (24–75 years) and the mean body mass index (BMI) was 27 (18–32). The range of duration of the preoperative symptoms was 6 months to 2 years. The average operating time dropped from 130 minutes for the first 12 cases to 90 minutes for the last 15 cases. The mean hospital stay was 3 days (range: 2–4 days). In the immediate postoperative period, 72% (n = 18) of the patients reported improvement in the GERD symptoms, while 2 (8%) patients described heartburn (grade I, mild, daily) and 1 (4%) patient described bloating (grade I, daily). A total of 5 patients (20%) reported mild dysphagia to solids in the first 2 postoperative weeks. These symptoms settled down after 2 to 5 weeks of postoperative proton-pump inhibitor (PPI) therapy and by adjusting consistency of oral feeds. There was no conversion to open, and we observed no perioperative mortality. There were no patients who underwent redo surgeries in the series. Conclusion LF is a safe and highly effective procedure for a patient with symptoms of GERD, and it gives long-term relief from the symptoms. Stringent selection criteria are necessary to optimize the results of surgery. Experience is associated with a significant reduction of operating time.

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