Effects of SARS-CoV­2 infections on inpatient mortality of geriatric patients after proximal femoral fracture surgery.

BACKGROUND: The medical challenges caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV­2) pose a tremendous burden on the healthcare system. This study aimed to analyze the effects of a SARS-CoV­2 infections or disease progression on inpatient mortality of geriatric patients after proximal femoral fracture surgery. METHODS: A retrospective analysis was conducted in all patients with a proximal femoral fracture surgically treated in an urban regional trauma center from 01/01/2020 to 01/31/2021. According to PCR test results detecting SARS-CoV­2, the patients were divided into two groups (SARS-CoV­2 positive vs. SARS-CoV­2 negative). Patient data, disease progression data, and treatment-related information were evaluated for all patients. Statistical data analysis was performed using unpaired Student's t test or non-parametric Mann-Whitney U test. RESULTS: A total of 311 patients (women: 70.4%, age: 82.0 ± 11.0 years) were included in this study. Of these 3.9% (12/311) had a positive test result for SARS-CoV­2. Significantly more deceased patients were found in the group tested positive for SARS-CoV­2 (SARS-CoV­2 positive: 41.7%, SARS-CoV­2 negative: 5.4%, p < 0.001). In addition, the number of proximal femoral fracture associated deaths correlated with the number of positive test results performed in the Clinic. The length of stay of SARS-CoV­2 COVID-19 survivors tended to be greater than in those who were tested negative (SARS-CoV­2 COVID-19 positive: 15.6 ± 13.1 days, SARS-CoV­2 COVID-19 negative: 11.5 ± 6.5 days, p = 0.683). Furthermore, a significant difference in age was found in SARS-CoV­2 survivors and SARS-CoV­2 decedents (deceased: 95.5 ± 7.5 years, alive: 83.5 ± 7.3 years, p = 0.020). CONCLUSION: The study was conducted before the introduction of SARS-CoV­2 vaccination. The results therefore refer to immune naive (unvaccinated) patients. In our study, more than 40% of all patients with proximal femoral fractures who tested positive for SARS-CoV­2 died during hospitalization. An additional, critical factor in this respect was the age of the infected patients. Nonetheless, a positive correlation was demonstrated between the mortality rate and the number of positive SARS-CoV­2 detections. Regarding the greater length of stay of patients tested positive for SARS-CoV­2, the limited transfer options (further rehabilitation, skilled nursing facility) of the infected ones can be considered as causal. Particularly the vulnerable older patients are increasingly endangered by a combination of proximal femoral fracture and SARS-CoV­2.

Fixation of intraoperative proximal femoral fractures during THA using two versus three cerclage wires - a biomechanical study.

BACKGROUND: Intraoperative proximal femoral fractures (IPFF) are relevant complications during total hip arthroplasty. Fixation using cerclage wires (CW) represents a minimally-invasive technique to address these fractures through the same surgical approach. The goal of treatment is to mobilise the patient as early as possible, which requires high primary stability. This study aimed to compare different cerclage wire configurations fixing IPFF with regard to biomechanical primary stability. METHODS: Standardised IPFF (type II, Modified Mallory Classification) were created in human fresh frozen femora and were fixed either by two or three CW (1.6 mm, stainless steel). All cadaveric specimens (n = 42) were randomised to different groups (quasi-static, dynamic) or subgroups (2 CW, 3 CW) stratified by bone mineral density determined by Dual Energy X-ray Absorptiometry. Using a biomechanical testing setup, quasi-static and dynamic cyclic failure tests were carried out. Cyclic loading started from 200 N to 500 N at 1 Hz with increasing peak load by 250 N every 100 cycles until failure occurred or maximum load (5250 N) reached. The change of fracture gap size was optically captured. RESULTS: No significant differences in failure load after quasi-static (p = 0.701) or dynamic cyclic loading (p = 0.132) were found between the experimental groups. In the quasi-static load testing, all constructs resisted 250% of the body weight (BW) of their corresponding body donor. In the dynamic cyclic load testing, all but one construct (treated by 3 CW) resisted 250% BW. CONCLUSIONS: Based on this in vitro data, both two and three CW provided sufficient primary stability according to the predefined minimum failure load (250% BW) to resist. The authors recommend the treatment using two CW because it reduces the risk of vascular injury and shortens procedure time.

Atraumatic femoral head necrosis: a biomechanical, histological and radiological examination compared to primary hip osteoarthritis.

INTRODUCTION: Atraumatic necrosis of the femoral head (AFHN) is a common disease with an incidence of 5000-7000 middle-aged adults in Germany. There is no uniform consensus in the literature regarding the configuration of the bone in AFHN. The clinical picture of our patients varies from very hard bone, especially in idiopathic findings, and rather soft bone in cortisone-induced necrosis. A better understanding of the underlying process could be decisive for establishing a morphology-dependent approach. The aim of this study is the closer examination of the condition of the bone in the AFHN compared to the primary hip osteo arthritis (PHOA). MATERIALS AND METHODS: The preparations were obtained as part of elective endoprosthetic treatment of the hip joint. Immediately after sample collection, thin-slice CT of the preserved femoral heads was performed to determine the exact density of the bone in the necrosis zone. Reconstruction was done in 0.8-1 mm layers in two directions, coronary and axial, starting from the femoral neck axis. Density of the femoral heads was determined by grey value analysis. The value in Hounsfield units per sample head was averaged from three individual measurements to minimize fluctuations. For biomechanical and histomorphological evaluation, the samples were extracted in the load bearing zone perpendicular to the surface of the femoral head. Group-dependent statistical evaluation was performed using single factor variance analysis (ANOVA). RESULTS: A total of 41 patients with a mean age of 64.44 years were included. The mean bone density of the AFHN samples, at 1.432 g/cm3, was about 7% higher than in the PHOA group with a mean value of 1.350 g/cm3 (p = 0.040). The biomechanical testing in the AFHN group showed a 22% higher-but not significant-mean compressive strength (20.397 MPa) than in the PHOA group (16.733 MPa). On the basis of histological analysis, no differentiation between AFHN and PHOA samples was possible. CONCLUSIONS: The present study (NCT, evidence level II) shows that AFHN has a very well detectable higher bone density compared to PHOA. However, neither biomechanical stress tests nor histomorphological evaluation did show any significant difference between the groups. The results allow the conclusion that there is no "soft" necrosis at all in the AFHN group.

Influence of the fixation technique on the mechanical properties of human cancellous bone of the femoral head.

BACKGROUND: The femoral head is of central importance for the force transmission from the suprapelvic body mass to the lower extremity. However, the condition of the subcortical bone and its mechanical properties in case of pathological changes due to coxarthrosis or femoral head necrosis differ from the healthy condition. METHODS: Fresh femoral heads were gathered during hip total endoprosthesis surgeries and cylindrical cancellous bone samples were extracted with a hollow drill. By means of a uniaxial tensile-compression test system, the compressive strength was determined for two different specimen types (fresh and 24 h storage in acetone). Exemplary tests on an exceptionally large femoral head were performed to compare properties of fresh, fresh-deep-frozen and acetone-stored samples. FINDINGS: The deformation behaviour and the material parameters determined were very heterogeneous. For most of the specimens, a destructive material test was successfully carried out, i.e. the compressive strength was determined. The average strength of fresh specimens was slightly higher than that of acetone specimens. On the other hand, the average Young's modulus of the acetone specimens was higher than that of the fresh specimens. INTERPRETATION: The lower Young's moodulus of the fresh samples compared to the acetone samples could indicate a causal effect of the degreasing influence of the acetone. The partly considerable individual differences in compressive strength and failure compression can have patient-specific influencing factors such as constitution and physical fitness as well as causes in the initial pathological condition.

Significance of nutritional status in the development of periprosthetic infections : A retrospective analysis of 194 patients.

BACKGROUND: Malnutrition caused by protein and vitamin deficiencies is a significant negative prognostic factor in surgical wound healing disorders and infections. Particularly in elective surgery, preoperative compensation of deficiencies is advisable to avoid negative postoperative consequences. This study examined the nutritional and protein balance of patients with periprosthetic hip and knee joint infections. MATERIAL AND METHODS: Patients with periprosthetic hip or knee joint infections constituted the study group (SG). Control group I (CG I) included patients with primary implants and CG II included patients who required revision surgery because of aseptic loosening. Relevant nutritional and protein parameters were determined via analysis of peripheral venous blood samples. In addition, a questionnaire was used to evaluate the nutritional and eating patterns of all patients. The nutritional risk screening (NRS) 2002 score and body mass index (BMI) were also calculated for all participants. RESULTS: Differences were found in the albumin level (SG: 36.23 ± 7.34, CG I: 44.37 ± 3.32, p < 0.001, CG II: 44.06 ± 4.24, p < 0.001) and total protein in serum (SG: 65.42 ± 8.66, CG I: 70.80 ± 5.33, p = 0.004, CG II: 71.22 ± 5.21, p = 0.004). The number of patients with lowered albumin levels (SG 19/61, CG I 1/78, CG II 2/55) and total protein in serum (SG: 12/61, CG I 5/78, CG II 2/55) also showed considerable variation. The number of patients with a NRS 2002 score ≥3 differed significantly between SG and both CGs (SG: 5/61, CG I 1/78, CG II 0/55); however, these differences could not be confirmed using BMI. CONCLUSION: As expected, lowered albumin and total protein levels were observed in PJI due to the acute phase reaction. The NRS can be performed to exclude nutritional deficiency, which cannot be excluded based on BMI. In cases of periprosthetic joint infection it is reasonable to compensate the nutritional deficiency with dietary supplements.

The impact of polyethylene abrasion on the occurrence of periprosthetic proximal femoral fractures in patients with total hip arthroplasty.

INTRODUCTION: In addition to abrasion-induced osteolysis and ensuing instabilities, the polyethylene (PE) abrasion of total hip arthroplasty (THA) inlays can also cause gait instability due to the decentralization of the hip joint. The current literature yields, as yet, insufficient findings whether these two factors are linked directly or indirectly to a higher risk for periprosthetic proximal femoral fractures (PPFF). The aim of our retrospective evaluation is to analyse the impact of PE abrasion on the pathology of PPFF in patients with THA. MATERIAL AND METHODS: The retrospective evaluation comprises all PPFF in patients with THA in the period from 01/2010 up to 12/2016. The study group (SG) included 66 cases (n = 66). The control group (CG) was comprised of patients with asymptomatic THA (n = 66), who were treated by our outpatient department including routine check-ups and X-ray examinations. We used the matched-pair methodology to scale the period of postsurgical care of the CG to the lifetime of the implant up to PPFF in the SG. We included epidemiologic data, radiological femoral head decentralization, osteolysis (Gruen classification), instabilities, acetabular cup position, and implant properties in our analysis. For the SG, we also included intra-operative signs of abrasion. FINDINGS: The SG showed significantly higher numbers of decentralized THA as signs of inlay erosion with 73% compared to only 41% in the CG (p > 0.001). The SG showed 1 ± 0.68 mm hip joint decentralization as to 0.5 ± 0.59 mm in the CG (p = 0.004). We found significantly more cases of osteolysis in the SG (n = 25) than in the CG (n = 13) (p = 0.003). We found no notable differences in acetabular cup inclination or anteversion as well as cup size. However, differences were significant in femoral head size (SG 32 ± 2.3 mm, CG 36 ± 2.4 mm; p = 0.042) and head material. We found more widespread use of metal femoral heads in the SG than in the CG (SG 1:1, CG 1:21; p = 0.001). CONCLUSION: PPFF patients showed significantly higher rates of inlay erosion, resulting in femoral head decentralization and osteolysis. The higher rate of fracture is likely caused by the increasing instability of the implant fixation due to abrasion-induced osteolysis and the associated degradation of bone quality. It is conceivable that the abrasion and decentralization of the THA can also lead to gait instability, and thus, a higher proneness to falls. Gait instability can also be aggravated by increased granulation tissue and effusion due to the inlay abrasion. Although this cannot be substantiated by the investigation. In patients with decentralization of the THA and osteolysis, a radiological follow-up should be performed, and in case of gait instability (femoral head and) inlay replacements should be considered.

Knee arthrodesis as last resort for persistent knee joint infections : Comparison of extramedullary and intramedullary treatment.

BACKGROUND: Knee joint arthrodesis is an established treatment for periprosthetic infections (PPI) providing stability and pain relief. In this study the outcome after arthrodesis of the knee joint for persistent infections was compared and evaluated depending on the surgical procedure (intramedullary vs. extramedullary). MATERIAL AND METHODS: In a retrospective case analysis, all patients who underwent knee joint arthrodesis between 1 January 2010 and 31 December 2016 were identified and divided into two groups: IMA and EMA. All patients were examined clinically and radiologically and the patient files were evaluated. In addition, the FIM score, the LEFS, the WHOQOL-BREF and NRS were evaluated. RESULTS: The median LEFS score for the IMA group was 26 points and in the EMA group 2 points (p = 0.03). The IMA patients showed a median pain scale at rest of 0 and during exercise of 2. The EMA group recorded a pain scale of 3 at rest and 5 during exercise (p = 0.28 at rest; p = 0.43 during exercise). In the IMA group the median postsurgical leg length difference was -2.0 cm and -2.5 cm in the EMA group (p = 0.31). At the end of the follow-up examinations, the FIM score of patients in the IMA group was 74.5 points and 22 points in the EMA group (p = 0.07). CONCLUSION: The study showed that no arthrodesis procedure is obviously superior with respect to the postoperative outcome. The IMA combines advantages especially in the early phase after surgery in terms of function as well as patient comfort and is therefore currently the procedure of choice. The attending physician should be familiar with the advantages and disadvantages of the various procedures in order to be able to make an individual decision and thus maximize the chance of treatment success.

Results after surgical treatment of periprosthetic proximal femoral fractures. Osteosynthesis with prosthesis preservation vs. prosthesis change.

Background: Periprosthetic fractures (PPF) of the femur close to the hip joint have serious consequences for most geriatric affected patients. In principle, apart from the highly uncommon conservative therapy, there are two therapeutic options. On the one hand, the prosthesis-preserving treatment by means of osteosynthesis using plates and/or cerclages in general is available. On the other hand, a (partial) change of the prosthesis with optionally additive osteosynthesis or a proximal femoral replacement can be performed because of prosthesis loosening or non-reconstructable comminuted fractures as well as most cemented stem variations. The aim of this retrospective study is the analysis of periprosthetic proximal femoral fractures in the presence of a total hip arthroplasty (THA). The outcome of the operated patients is to be investigated depending on the type of care (osteosynthesis with prosthesis preservation vs. prosthesis change). Material and methods: In a retrospective case analysis, 80 patients with THA and PPF were included. They were divided into two groups. Group I represents the osteosynthetic treatment to preserve the implanted THA (n=42). Group II (n=38) includes those patients who were treated by a change of their endoprosthesis with or without additional osteosynthesis. Specifics of all patients, like gender, age at fracture, interval between fracture and implantation, length of in-patient stay, body mass index, osteoporosis, corticomedullary index and complications such as infections, re-fracture, loosening, material failure or other complications, were recorded and compared. Furthermore, the patients were re-examined by a questionnaire and the score according to Merle d'Aubigné and Postel. Results: In group I the mean follow-up time was 48.5±23 months (4 years) whereas group II amounted 32.5±24.5 months (2.7 years) (p=0.029). Besides, there were significant differences in age (81± 11 years vs. 76±10 years, p=0.047) and length of in-patient stay (14.5±8.6 days vs. 18.0±16.7 days, p=0.014). According to the score of Merle d'Aubigné and Postel, there were significantly better values for the pain in group II with comparable values for mobility and walking ability. Conclusion: The treatment of periprosthetic proximal fractures of the femur is dependent on the classification (Vancouver and Johannsen) and in particular on the prosthetic anchoring as well as the extent of the comminution zone. Older patients and patients with osteoporosis are more frequently treated with an endoprosthesis revision. Patients, who have been treated with an osteosynthesis for preserving their endoprosthesis, showed a shorter length of in-patient stay and fewer complications than people with replacement surgery. In contrast to that, patients with prosthesis revision had better outcomes concerning the score of Merle d'Aubigné and Postel.

The reliability of a restraint sensor system for the computer-supported detection of spinal stabilizing muscle deficiencies.

BACKGROUND: The presence of muscular deficiency seems to be a major cause of back pain that requires counteractions. Considering that the autochthonous back muscles, responsible for straightening and stabilizing the spine, cannot be activated voluntarily, they can be strengthened only through specific training. The computer-supported test and training system (CTT) Centaur (BfMC GmbH, Leipzig, SN, Germany) seems well suited for this purpose. To show its potential as a reliable diagnostic and training tool, this study aimed to evaluate the test-retest reliability of this 3D spatial rotation device. METHODS: A prospective pilot study was conducted in 20 healthy volunteers of both sexes. For test-retest reliability analysis, three measurements were performed with a two-day interval between each measurement. Each measurement consisted of a one-minute endurance test performed in eight different positions (transverse plane). During the test, the subject was tilted by 90° in the sagittal plane from a neutral, upright position. Meanwhile, the subject's level of upper body stabilization along the body axis was assessed. All trunk movements (momentum values) were quantified by a multicomponent force sensor and standardized relative to the subject's upper body mass. The range of motion was assessed by 95% confidence ellipse analysis. Here, all position-specific confidence ellipses for each measurement were merged to a summarized quantity. Finally, ICC analysis using a single-rating, absolute agreement, two-way mixed-effects model and a Bland-Altman plot was performed to determine the reliability. RESULTS: Considering all measurements (t1, t2, t3), the ICC for reliability evaluation was 0.805, and the corresponding 95% confidence interval (CI) was [0.643, 0.910]. Moreover, the Bland-Altman plots for all three pairs of time points did not show significant differences. CONCLUSION: This study concludes that the CTT Centaur shows good test-retest reliability, indicating it can be used in clinical practice in the future.

The significance of the vitamin D metabolism in the development of periprosthetic infections after THA and TKA: a prospective matched-pair analysis of 240 patients.

BACKGROUND: The importance of the vitamin D homeostasis in infections is already known. However, its significance in periprosthetic infections (PPIs) after total hip arthroplasty and total knee arthroplasty is largely unexplored. The aim of the study is to precisely analyze the vitamin D balance in patients with PPIs after total hip arthroplasty and total knee arthroplasty. Here, cases with primary endoprosthesis implants and aseptic loosening are used as comparison groups. MATERIALS AND METHODS: In this prospective matched-pair analysis, patients with PPI at the hip and knee joints were included in the study group (SG). The control groups (CGs) consisted of patients with primary implants (CG I) and who underwent replacement surgery due to aseptic loosening (CG II). In addition to 25 OH vitamin D3 and calcium, bone mineral and protein parameters were determined. An osteoporosis-specific questionnaire was collected. RESULTS: There are no significant differences in the 25 OH-vitamin D levels between the SG (17.9±8.9) and both CGs (CG I: 16.8±6.90; CG II: 19.7±7.90). However, compared with the SG, significantly higher levels of calcium (Ca) and bone-specific alkaline phosphatase were found in both CGs in comparison with the SG. Significantly lower values concerning the protein balance in PPI were conspicuous. Acute PPI showed a significant reduction in 25 OH vitamin D3 compared with chronic infections (8.3±5.98 vs 21.6±8.40, P=0.002). Calcium and protein balance were also significantly reduced in acute PPIs. CONCLUSION: Acute PPIs of the hip and knee joints show a significantly reduced calcium and 25 OH vitamin D3 levels as well as lowered proteins (albumin and total protein) compared with chronic infections as well as primary endoprostheses and aseptic replacement operations. Substitution of vitamin D3 and calcium with simultaneous adaptation of the protein balance is recommended in all PPIs, especially in the acute PPI.

A new classification of TKA periprosthetic femur fractures considering the implant type.

BACKGROUND: The treatment aims of periprosthetic fractures (PPF) of the distal femur are a gentle stabilization, an early load-bearing capacity and a rapid postoperative mobilization of the affected patients. For the therapy planning of PPF a standardized classification is necessary which leads to a clear and safe therapy recommendation. Despite different established classifications, there is none that includes the types of prosthesis used in the assessment. For this purpose, the objective of this work is to create a new more extensive fracture and implant-related classification of periprosthetic fractures of the distal femur based on available classifications which allows distinct therapeutic recommendations. METHODS: In a retrospective analysis all patients who were treated in the University Hospital Leipzig from 2010 to 2016 due to a distal femur fracture with total knee arthroplasty (TKA) were established. To create an implant-associated classification the cases were discussed in a panel of experienced orthopaedists and well-practiced traumatologists with a great knowledge in the field of endoprosthetics and fracture care. In this context, two experienced surgeons classified 55 consecutive fractures according to Su et al., Lewis and Rorabeck and by the new created classification. In this regard, the interobserver reliability was determined for two independent raters in terms of Cohen Kappa. RESULTS: On the basis of the most widely recognized classifications of Su et al. as well as Lewis and Rorabeck, we established an implant-dependent classification for PPF of the distal femur. In accordance with the two stated classifications four fracture types were created and defined. Moreover, the four most frequent prosthesis types were integrated. Finally, a new classification with 16 subtypes was generated based on four types of fracture and four types of prosthesis. Considering all cases the presented implant-associated classification (κ = 0.74) showed a considerably higher interobserver reliability compared to the other classifications of Su et al. (κ = 0.39) as well as Lewis and Rorabeck (κ = 0.31). Excluding the cases which were only assessable by the new classification, it still shows a higher interobserver reliability (κ = 0.70) than the other ones (κ = 0.63 or κ = 0.45). CONCLUSIONS: The new classification system for PPF of the distal femur following TKA considers fracture location and implant type. It is easy to use, shows agood interobserver reliability and allows conclusions to be drawn on treatment recommendations. Moreover, further studies on the evaluation of the classification are necessary and planned.

Evaluation of a multimodal pain therapy concept for chronic pain after total knee arthroplasty: a pilot study in 21 patients.

BACKGROUND: In spite of the improvement of many aspects around Total knee arthroplasty (TKA), there is still a group of 10% to 34% of patients who is not satisfied with the outcome. The therapy of chronic pain after TKA remains a medical challenge that requires an interdisciplinary therapy concept. The aim of this prospective pilot study was to evaluate the efficacy of a multimodal pain therapy in chronic complaints after TKA. METHODS: In a prospective cohort pilot study, we included patients with chronic pain after TKA who obtained in-patient care, especially multimodal pain therapy (MMPT), for at least 10 days. Essential elements of this therapy concept were physiotherapy, pain medication therapy, topical application of ketamine, local infiltration and Traditional Chinese Medicine. Patients with varying causes of complaints were excluded in advance. Before the start of the study all test persons were informed and gave their written consent. Moreover, each patient was examined and questioned at hospital admission, discharge and at its first as well as second follow-up. Additionally, knee joint mobility and stability were investigated at all examination times. RESULTS: From 03/07/2016 to 07/14/2016, 21 patients were included in the pilot study. 52% of the considered population were female (11 persons). The median age was 65 years (45-79 years) and the median stay in hospital amounted 9 days (8-14 days). The first follow-up was scheduled after six weeks (median: 38 days, 30-112 days) and the second one after six months (median: 8 months, 7-12 months). The number of patients of the first follow-up was 17 out of 21 (19% drop out). The drop out of the last follow-up accounted for 33%. All patients benefit from the presented applications and therapies with regard to pain, function and range of motion. Especially, during the period of in-patient treatment, nearly all patients have improved in all terms. However, during the first follow-up clear deteriorations occurred in all areas, which stagnated up to the second follow-up. The range of motion has even worsened slightly. CONCLUSIONS: With the presented pilot study on multimodal in-patient therapy of chronic complaints due to TKA, the improvement of pain, function and mobility could be verified, especially during the stationary stay. Even though the results deteriorate during the follow-up period, they did never relapse to their initial level. In order to ensure an effective treatment, a clear diagnostic algorithm is essential, by which treatable causes, such as low-grade infections or loosenings, are safely excluded. Further prospective studies are necessary to obtain precise statements on prospects of success of our therapy plan.

Treadmill based reference running data for healthy subjects is dependent on speed and morphological parameters.

OBJECTIVE: To obtain spatiotemporal and dynamic running parameters of healthy participants and to identify relationships between running parameters, speed, and physical characteristics. METHOD: A dynamometric treadmill was used to collect running data among 417 asymptomatic subjects during speeds ranging from 10 to 24km/h. Spatiotemporal and dynamic running parameters were calculated and measured. RESULTS: Results of the analyses showed that assessing running parameters is dependent on running speed. Body height correlated with stride length (r=0.5), cadence (r=-0.5) and plantar forefoot force (r=0.6). Body mass also had a strong relationship to plantar forefoot forces at 14 and 24km/h and plantar midfoot forces at 14 and 24km/h. CONCLUSION: This reference data base can be used in the kinematic and kinetic evaluation of running under a wide range of speeds.