scholarly journals Titanium Acetabular Component Deformation under Cyclic Loading

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 52
Author(s):  
Nicholas A. Beckmann ◽  
Rudi G. Bitsch ◽  
Theresa Bormann ◽  
Steffen Braun ◽  
Sebastian Jaeger

Acetabular cup deformation may affect liner/cup congruency, clearance and/or osseointegration. It is unclear, whether deformation of the acetabular components occurs during load and to what extent. To evaluate this, revision multi-hole cups were implanted into six cadaver hemipelvises in two scenarios: without acetabular defect (ND); with a large acetabular defect (LD) that was treated with an augment. In the LD scenario, the cup and augment were attached to the bone and each other with screws. Subsequently, the implanted hemipelvises were loaded under a physiologic partial-weight-bearing modality. The deformation of the acetabular components was determined using a best-fit algorithm. The statistical evaluation involved repeated-measures ANOVA. The mean elastic distension of the ND cup was 292.9 µm (SD 12.2 µm); in the LD scenario, 43.7 µm (SD 11.2 µm); the mean maximal augment distension was 79.6 µm (SD 21.6 µm). A significant difference between the maximal distension of the cups in both scenarios was noted (F(1, 10) = 11.404; p = 0.007). No significant difference was noted between the compression of the ND and LD cups, nor between LD cups and LD augments. The LD cup displayed significantly lower elastic distension than the ND cup, most likely due to increased stiffness from the affixed augment and screw fixation.

2018 ◽  
Vol 4 (1) ◽  
pp. e000326 ◽  
Author(s):  
Stephen G Thompson ◽  
Rhodri D Phillip ◽  
Andrew Roberts

AimTo compare the interpretation of toe touch weight bearing (TTWB) and partial weight bearing (PWB) among orthopaedic surgeons, rehabilitation professionals and patients.Methodology78 consultant and middle-grade orthopaedic surgeons in the UK completed a questionnaire. 64 rehabilitation professionals (including physiotherapists) at Defence Medical Rehabilitation Centre Headley Court were also recruited. Both groups provided their interpretation of TTWB and PWB as a percentage of total body weight (%TBW). Each rehabilitation professional, then applied what they interpreted to be TTWB and PWB using a Lasar Posture weighing device. The predicted values were compared with the actual values demonstrated.ResultsThere was no significant difference between orthopaedic surgeons and rehabilitation professionals in their interpretation of TTWB and PWB, however there was a wide range of responses. There was a significant difference between the predicted %TBW and the actual values demonstrated by the ‘educated patient’ (mean difference 4.8 (TTWB) and 22.9 (PWB)).ConclusionHealthcare professionals vary greatly in their interpretation of the terms TTWB and PWB. Therefore, for a consistency in rehabilitation delivery the terms should not be used in isolation without a further descriptor. Static measures of weight application are lower than people think they are applying. We encourage the use of loading practice with a scale to reassure and educate patients.


2020 ◽  
Vol 140 (12) ◽  
pp. 1947-1954
Author(s):  
Johannes Becker ◽  
M. Winkler ◽  
C. von Rüden ◽  
E. Bliven ◽  
P. Augat ◽  
...  

Abstract Introduction Aim of this study was to biomechanically compare two different acetabular cup fixation constructs in terms of fracture fixation for displaced acetabular fractures involving the anterior column with hemitransverse fracture under partial and full weight-bearing conditions. Methods Two different reinforcement rings designed as cages for primary THA were biomechanically tested in terms of managing a complex acetabular fracture. Single-leg stance cyclic loading was performed to assess fracture gap movement and fragment rotation. Twelve hemi pelvis Sawbones were divided into two groups: primary THA with acetabulum roof reinforcement plate (ARRP) (n = 6) and primary THA with Burch–Schneider reinforcement cage (BSRC) (n = 6). Results During loading under partial weight-bearing (250 N) fracture gap movement tended to be larger in the BSRC group as compared to the ARRP group. Under full weight-bearing conditions, the ARRP showed 60% significantly less motion (p = 0.035) of the os ilium to os ischii gap compared to BSRC. Fracture gap movements between the os ilium and spina iliaca fragments were significantly reduced by 76% (p = 0.048) for ARRP in contrast to BSRC. The ARRP group also demonstrated significantly less movement in the fracture gaps os ischii to quadrilateral plate (62% reduction, p = 0.009) and quadrilateral plate to spina iliaca (87% reduction, p < 0.001). Significantly less rotational movement of the quadrilateral plate to the os ilium was exhibited by the ARRP group (p = 0.015). Conclusions The presented acetabulum roof-reinforcement plate (ARRP) provides stable conditions at the acetabular component with adequate stabilization of a displaced acetabular fracture.


2021 ◽  
Vol 12 ◽  
pp. 215145932110558
Author(s):  
Martin Paulsson ◽  
Carl Ekholm ◽  
Eythor Jonsson ◽  
Mats Geijer ◽  
Ola Rolfson

Introduction After surgery for distal femur fractures in elderly patients, weight-bearing is commonly restricted. Immediate non-restrictive weight-bearing might have beneficial effects. There are no randomized studies on the topic. The purpose of this study was to compare the functional outcome between immediate full weight-bearing (FWB) as tolerated and partial weight-bearing (PWB) during the first 8 weeks following plate fixation of distal femur fractures in elderly patients. Methods Patients aged 65 years or older with distal femur fractures of AO/OTA types 33 A2, A3, B1, B2, C1, and C2 were included. Exclusion criteria were impaired cognitive function, concomitant injuries, or inability to follow the postoperative regimen. Internal fixation was achieved with an anatomical lateral distal femur plate applied as a strictly bridge-plating construct. The primary outcome measure was the function index of the short musculoskeletal functional assessment (SMFA) after 52 weeks from injury. Results Thirty-two patients were randomized to FWB (n = 11) or PWB (n = 21). After 16 and 52 weeks, there were no differences in the mean SMFA function index between FWB and PWB (36 vs 43, P = .42 and 52 vs 40, P = .18, respectively) nor in the mean EuroQol 5-dimension index or range of motion (ROM). Overall, the SMFA function index was higher at 52 weeks compared with before injury (44 vs 30, P = .001) as was the mean bothersome index (37 vs 21, P = .011). There was no clear difference in the occurrence of adverse events between the treatment groups. Conclusions There were no differences in functional outcome, adverse events, or ROM between immediate FWB and PWB following plate fixation for a distal femur fracture in elderly patients. A distal femur fracture has a negative effect on the functional status of elderly patients that persists at least up to 1 year following injury.


Author(s):  
Ujjwal K. Debnath ◽  
S. Naidu Maripuri ◽  
K. N. Subramanian ◽  
K. Mohanty

<p class="abstract"><strong>Background:</strong> <span lang="EN-IN">Biomechanical testing, intramedullary devices have proven advantageous over the extramedullary devices in the management of unstable intertrochanteric fractures. Reverse oblique type of intertrochanteric fractures are highly unstable and intramedullary nails are currently the method of internal fixation. The currently available nails seems to provide rotational, axial and angular stability, but biomechanical analysis of the strain pattern in the bone and implant in this fractures are lacking. The aim of this experimental study was to analyse the strain in three different long femoral nail-bone units under physiological loading when implanted in Saw bone model after creating a reverse oblique intertrochanteric fracture.</span></p><p class="abstract"><strong>Methods:</strong> A total of 12 sawbones were divided in to 4 equal groups. Group 1 was intact saw bones and were used as controls. Group 2, Group 3 and Group 4 were implanted with Depuy, Stryker and Synthes nails respectively after creating a reverse oblique intertrochanteric fracture. All the four groups were axially loaded with 100 N increments until physiological loads. The strain patterns were measured at the posteromedial cortex and the peak strains were extracted at partial weight bearing i.e. 500 N and full weight bearing physiological loads i.e. 1000 N.<strong></strong></p><p class="abstract"><strong>Results:</strong> <span lang="EN-IN">There was no significant difference in peak strains among the groups at partial loads. However at 1000 N loads the peak strain in the DePuy nail-bone unit was significantly high compared to the other two nail-bone units and the controls. </span></p><p class="abstract"><strong>Conclusions:</strong> These results question the safety of immediate full weight bearing following surgery when treating the reverse oblique unstable fractures with DePuy intramedullary nails. A period of partial weight bearing following fixation of reverse oblique fractures would be wise when using DePuy nails<span lang="EN-IN">.</span></p>


Author(s):  
Franziska Leiss ◽  
Julia Sabrina Götz ◽  
Matthias Meyer ◽  
Günther Maderbacher ◽  
Jan Reinhard ◽  
...  

Abstract Background Femoral component subsidence is a known risk factor for early failure of total hip arthroplasty (THA) using cementless stems. The aim of the study was to compare an enhanced recovery concept with early full weight-bearing rehabilitation and partial weight-bearing on stem subsidence. In addition, the influence of patient-related and anatomical risk factors on subsidence shall be assessed. Methods One hundred and fourteen patients underwent primary cementless THA and were retrospectively analyzed. Sixty-three patients had an enhanced recovery rehabilitation with early full weight-bearing and 51 patients had rehabilitation with partial weight-bearing (20 kg) for 6 weeks. Postoperative subsidence was analyzed on standing pelvic anterior–posterior radiographs after 4 weeks and 1 year. Subsidence was measured in mm. Anatomical and prosthetic risk factors (stem size, canal flare index, canal fill ratio as well as BMI and demographic data) were correlated. Results Femoral stem subsidence rate was significantly higher for the group with an enhanced recovery concept compared to the group with partial weight-bearing at the first radiological follow up after 4 weeks [2.54 mm (SD ± 1.86) vs. 1.55 mm (SD ± 1.80)] and the second radiological follow up after 1 year [3.43 mm (SD ± 2.24) vs. 1.94 (SD ± 2.16)] (p < 0.001, respectively). Stem angulation > 3° had a significant influence on subsidence. Canal flare index and canal fill ratio showed no significant correlation with subsidence as well as BMI and age. Conclusion In the present study, cementless stem subsidence was significantly higher in the group with enhanced recovery rehabilitation compared to partial weight-bearing. Small absolute values and differences were demonstrated and therefore possibly below clinical relevance. Anatomical radiological parameters and anthropometric data did not appear to be risk factors for stem subsidence.


SICOT-J ◽  
2018 ◽  
Vol 4 ◽  
pp. 16 ◽  
Author(s):  
Hélder Fonte ◽  
Ricardo Rodrigues-Pinto

Introduction: Femoral neck stress fractures are uncommon and depending on their location, can be at high risk for non-union and significant morbidity.  Their prevalence is higher among runners and military recruits, and women seem to be at higher risk. Methods: A 27-year-old female, who was enrolled in military recruit, reported left side groin pain after a strenuous running exercise. Due to persistent pain an X-Ray was ordered, which revealed no signs of acute lesions. Further imaging studies with CT scan and MRI identified a compression-type femoral neck stress fracture. Results: The patient was submitted to conservative treatment consisting of restricting from full weight-bearing. Six weeks after she initiated partial weight-bearing, becoming asymptomatic at seven months. Follow-up imaging studies revealed union of the fracture. Discussion: This diagnosis should be considered when evaluating military and athlete populations. Early recognition of these injuries is crucial because complication and morbidity rates are high.


2021 ◽  
Vol 15 (6) ◽  
pp. 1589-1593
Author(s):  
Elham Shahraki Moghadam ◽  
Zahrasadat Manzari ◽  
Hossein Rashki Ghalenow ◽  
Hajar Noori Sanchooli

Background: Common clinical problems after surgery include nausea, vomiting and ileus that many patients complain of after their surgery. These complications can delay the patient's discharge from hospital. Nowadays, to reduce drug side effects, the use of complementary medicine, including reflexology, has received a great deal of attention. Aim: To compare the effect of hand and foot reflexology massages on the severity of nausea, vomiting and ileus in patients after abdominal surgery. Methods: This is a clinical trial study that was conducted between 2013 and 2015 in the emergency surgical departments of Imam Reza (AS) and Ghaem (AS) hospitals in Mashhad. The samples of this study included 90 women with cholecystitis and appendicitis who met the inclusion criteria. In this study, patients were randomly divided into 3 groups of hand reflexology massage, foot reflexology massage and control. To check the digestive status, gastrointestinal sounds were checked every hour using a clinical stethoscope. Also, information on gas and feces elimination was collected and recorded every hour. The intervention was performed 1 and 12 hours after the surgery. In both groups of hands and foot reflexology massages, after general massage of the hands and feet, the areas related to the abdominal distension and removal of the ileus were pressed. It should be noted that, the duration of massage for each person was 10 minutes (20 minutes in total). Data were analyzed by SPSS software version 16 using Chi-square, Fisher’s exact test, two-way ANOVA, Kruskal-Wallis test and repeated measures ANOVA. Results: There was no statistically significant difference in the mean score of severity of nausea before the intervention between the three groups (p = 0.90), but after the intervention a significant difference was observed in the mean score of severity of nausea between the three groups (p=0.002). Also, the result of ANOVA test with repeated measure showed a statistically significant difference in the mean score of nausea by group and stage (p<0.001). There was also no statistically significant difference in the frequency of vomiting severity between the three groups after the intervention. However, at 4 and 24 hours after the intervention, a statistically significant difference was observed between the three groups in that regard. Conclusion: The results showed that both types of hand and foot reflexology massage has positive effects on nausea and return of gastrointestinal movements, so nurses can use reflexology as a non-pharmacological and complementary method to reduce the severity of nausea and return gastrointestinal movements in postoperative patients. Since the reflexology had little or no effect on the severity of vomiting and the acceleration of gastrointestinal movements in patients, further studies in this area are recommended. Keywords: Reflexology, Pain, Nausea and vomiting, Ileus, Surgery


2020 ◽  
Vol 5 (4) ◽  
pp. 2473011420S0032
Author(s):  
Thomas L. Lewis ◽  
Robbie Ray; David Gordon

Category: Bunion Introduction/Purpose: Minimally invasive surgery for hallux valgus has significantly increased in popularity recently due to smaller incisions, reduced soft tissue trauma, and the ability to achieve large deformity corrections compared to traditional treatments. This study aimed to investigate the radiological outcomes and degree of deformity correction of the intermetatarsal angle (IMA) and the hallux valgus angle (HVA) following third generation (using screw fixation) Minimally Invasive Chevron and Akin Osteotomies (MICA) for hallux valgus. Methods: A single surgeon case series of patients with hallux valgus underwent primary, third generation MICA for hallux valgus. Pre- and post-operative (6 weeks after surgery) radiological assessments of the IMA and HVA were based on weight-bearing dorso-plantar radiographs. Radiographic measurements were conducted by two foot & ankle fellowship trained consultant surgeons (RR, DG). Paired t-tests were used to determine the statistically significant difference between pre- and post-operative measurements. Results: Between January 2017 and December 2019, 401 MICAs were performed in 274 patients. Pre- and post-operative radiograph measurements were collected for 348 feet in 232 patients (219 female; 13 male). The mean age was 54.4 years (range 16.3-84.9, standard deviation (s.d.) 13.2). Mean pre-operative IMA was 15.3° (range 6.5°-27.0°, s.d. 3.4°) and HVA was 33.8° (range 9.3°-63.9°, s.d. 9.7°). Post-operatively, there was a statistically significant improvement in radiological deformity correction; mean IMA was 5.3° (range -1.2°-16.5°, s.d. 2.7°, p<0.001) and mean HVA was 8.8° (range -5.2°-24.0°, s.d. 4.5°, p<0.001). The mean post-operative reduction in IMA and HVA was 10.0° and 25.0° respectively. Conclusion: This is the largest case series demonstrating radiological outcomes following third generation Minimally Invasive Chevron and Akin Osteotomies (MICA) for hallux valgus to date. These data show that this is an effective approach at correcting both mild and severe hallux valgus deformities. Longer term radiological outcome studies are needed to investigate whether there is any change in radiological outcomes. Correlation with patient reported outcomes is planned.


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