Quality of life and functional outcome of periprosthetic fractures around the knee following knee arthroplasty.

PURPOSE OF THE STUDY The present study aimed to analyse both, the functional outcome and quality of life after surgical treatment of periprosthetic fractures following TKA. MATERIAL AND METHODS A retrospective review of all periprosthetic fractures following knee arthroplasty which have been surgically treated at our institution between January 2005 and January 2012 was conducted. Beside epidemiologic data, type of surgery and postoperative complications were recorded. The functional outcome was assessed using range of motion, Knee Society Score and VAS to evaluate pain. Quality of life was evaluated using SF-36 and WOMAC. Furthermore patients mobility and comorbidities were analysed. RESULTS 25 (mean age 76 ± 8 years; m:w 5:20) patients were included. The overall complication rate was 24%. Mean KSS knee score was 73 ± 19 and a function score was 41 ± 36. Range of motion revealed 95° ± 24° (active) and 98° ± 16° (passive). The total SF-36 scored a mean of 41 ± 6 and 29 ± 19 in average considering the WOMAC index (pain: 19 ± 20; stiffness: 23 ± 27; daily: 47 ± 29). 20% were able to mobilise without help as opposed to 80% that were in need for assistance. Our analysis revealed no influence of the final outcome as a function of fracture type or type of treatment. Multiple regression analysis could not reveal significant influence of the comorbidities. CONCLUSION Periprosthetic fractures following knee arthroplasty are accompanied by a significant decrease of the knee function and quality of life as well as high complication rates. Since patient's quality of life apparently depends on the functional outcome, future efforts should aim to improve these parameters. Key words: periprosthetic fracture, total knee arthroplasty, quality of life, functional outcome, locking plate.

["Pediatric inflammatory multisystem syndrome"-Experiences from a Berlin Children's Hospital]. / "Pediatric inflammatory multisystem syndrome" ­ Erfahrungen aus einer Berliner Kinderklinik.

BACKGROUND: Since the beginning of the SARS-CoV­2 pandemic, cases of the hyperinflammatory syndrome pediatric inflammatory multisystem syndrome (PIMS) have been accumulating. The clinical presentation is variable and it occurs 2-6 weeks after infection with SARS-CoV­2. As of today, immunoglobulins and/or steroids as well as ASS are used for medication. METHOD: In our clinic 11 patients presented with PIMS between 06/2020 and 06/2021, whose data were retrospectively collected and analyzed. RESULTS: Of the 11 patients 6 were male, the age distribution ranged from 4-18 years and 7 were overweight or obese. Almost all patients showed gastrointestinal and cardiovascular involvement, 4 had respiratory symptoms, 6 showed signs of nephritis. All showed blood count changes with anemia or leukocytosis and coagulopathy. CRP, ferritin, and soluble IL2 receptor were highly elevated in all patients. Only 2 patients had neither troponin­T nor NT-pro-BNP elevation and 7 patients had impaired left ventricular function. Positive SARS-CoV­2 serology was found in 10, and positive SARS-CoV­2 PCR via nasopharyngeal swabs in 2.All were initially treated with antibiotics, 3 patients required O2 supplementation, 6 required intensive care and 5 required vasoactive agents. All but one patient received immunoglobulins and ASS, 5 received prednisolone. Length of stay ranged from 4-51 days. CONCLUSION: PIMS is a severe acute hyperinflammatory disease, which was secured in 11 patients in our clinic. In some cases, there was a need for intensive care. Under anti-inflammatory therapy there was a good response without exception.

Cardiac disease and advanced age increase the mortality risk following surgery for periprosthetic femoral fractures.

AIMS: Periprosthetic fracture is a significant complication of total hip and knee arthroplasty. This study aimed to describe the survival of patients sustaining periprosthetic femoral fractures and compare this with that of the general population, as well as to identify the factors that influence survival. PATIENTS AND METHODS: A total of 151 patients (women: men 116:35, mean age 74.6 years, standard deviation 11.5) that sustained a periprosthetic fracture between January 2005 and October 2012 were retrospectively analysed. Epidemiological data, comorbidities, type of surgical management, type of implant, and mortality data were studied. RESULTS: The mean survival time was 77 months (95% confidence interval 71 to 84; numbers at risk: 73) and was lower than that of the general population. The risk analyses showed that previous cardiac disease, particularly ischaemic heart disease, cardiac arrhythmias, and heart failure, age over 75 years and American Society of Anesthesiologists (ASA) scores above 3 were associated with a significantly higher mortality. CONCLUSIONS: Periprosthetic fractures carry a high risk of post-operative mortality. Our data demonstrate that advanced age (> 75 years) and previous cardiac disease are associated with a significantly higher risk of mortality. The ASA score is an appropriate instrument for risk stratification. Pre-operative cardiac status should be optimised before surgery. Cite this article: Bone Joint J 2017;99-B:921-6.

Myoelectric evoked potentials versus locomotor recovery in chronic spinal cord injured rats.

The purpose of this study was to determine the utility of descending evoked potentials in evaluating functional recovery in rats after spinal cord contusion injury. Rats received thoracic contusions at T9 using a controlled-displacement impactor. They were evaluated for 5 weeks postinjury using auditory startle responses (ASR) while alert, or by cerebellar motor evoked potentials (CMEP) while anesthetized. ASR and CMEP were recorded electromyographically from forelimb and hindlimb muscles. Open field locomotor performance was also assessed and recovered to almost normal levels by 3 weeks postinjury. Histologic analysis of the injury site indicated that the contusions destroyed approximately 70% of the cross-sectional area of the cord. Although the remaining 30% was sufficient to preserve nearly normal locomotor behavior, ASR and CMEP amplitudes in hindlimb flexors and extensors were reduced by 90% or more after injury and showed virtually no recovery. Significant ASR and CMEP responses were present in the cutaneous trunk muscles of the lower torso after injury. These muscles are innervated via peripheral nerves originating at cord levels above the injury. Multi-wave field potentials normally recorded from the dorsal cord surface in response to cerebellar stimulation were absent in injured rats, suggesting minimal if any activation of segmental neurons via the pathways normally mediating CMEP. The tracts mediating ASR and CMEP thus appear to be highly sensitive to mild spinal cord trauma but are evidently not essential for support or walking.

MASCIS evaluation of open field locomotor scores: effects of experience and teamwork on reliability. Multicenter Animal Spinal Cord Injury Study.

The Multicenter Animal Spinal Cord Injury Study (MASCIS) adopted a modified 21-point open field locomotor scale developed by Basso, Beattie, and Bresnahan (BBB) at Ohio State University (OSU) to measure motor recovery in spinal-injured rats. BBB scores categorize combinations of rat hindlimb movements, trunk position and stability, stepping, coordination, paw placement, toe clearance, and tail position, representing sequential recovery stages that rats attain after spinal cord injury. A total of 22 observers from 8 participating centers assessed 18 hindlimbs of 9 rats at 2-6 weeks after graded spinal cord injury. The observers were segregated into 10 teams. The teams were grouped into 3 cohorts (A, B, and C), consisting of one experienced team from OSU and two non-OSU teams. The cohorts evaluated the rats in three concurrent and sequential sessions. After viewing a rat for 4 min, individual observers first assigned scores without discussion. Members of each team then discussed and assigned a team score. Experience (OSU vs. non-OSU) and teamwork (individual vs. team) had no significant effect on mean scores although the mean scores of one cohort differed significantly from the others (p = 0.0002, ANOVA). However, experience and teamwork significantly influenced reliability of scoring. OSU team scores had a mean standard deviation or discordance of 0.59 points, significantly less than 1.31 points for non-OSU team scores (p = 0.003, ANOVA) and 1.30 points for non-OSU individual scores (p = 0.001, ANOVA). Discordances were greater at the upper and lower ends of the scale, exceeding 2.0 in the lower (< 5) and upper (> 15) ends of the scale but were < 1.0 for scores between 4 and 16. Comparisons of non-OSU and OSU team scores indicated a high reliability coefficient of 0.892 and a correlation index (r2) of 0.894. These results indicate that inexperienced observers can learn quickly to assign consistent BBB scores that approach those given by experienced teams, that the scores are most consistent between 4 and 16, and that experience improves consistency of team scores.

Comparison of vestibular and auditory startle responses in the rat and cat.

Cats, humans, and many other animals show stereotyped EMG responses in limb and axial muscles if suddenly dropped into free-fall. In cats, these free-fall responses (FFR) consist of highly synchronized bursts in most limb and axial muscles at 18-22 ms. We have used FFR to evaluate descending motor function and recovery in chronic spinal injured cats. Here FFR are compared with auditory evoked startle reflexes (ASR) in the hindlimb muscles of the rat and cat to determine whether they are related, and whether they could be used to evaluate descending motor function in the rat. ASR and FFR in the two species were similar except that the earliest components for both responses occurred around 9 ms in the rat versus 18-20 ms in the cat. Also, FFR in cats were usually more consistent and greater in amplitude during repeated drops than in rats, while the converse was true for ASR. Rat FFR amplitudes increased significantly after administering ketamine or 4-aminopyridine (4-AP), especially with both drugs together, while ASR amplitudes did not. FFR in cats recorded under ketamine analgesia were not normally improved by 4-AP. Finally, both FFR and ASR were suppressed by pentobarbital, chloralose, or motor activity. These data suggest that: (1) FFR appears to be a vestibular evoked startle reflex; (2) in the rat, ASR should be useful as a test of descending motor function following spinal injury, and (3) the combination of ketamine and 4-AP may be useful in revealing the presence of functional spinal pathways after CNS trauma.

4-Aminopyridine enhances motor evoked potentials following graded spinal cord compression injury in rats.

Although several experimental and clinical studies have demonstrated the ability of 4-aminopyridine (4-AP) to restore electrophysiological and/or behavioral function following chronic spinal cord injury, the mechanism by which this occurs remains unclear. Demonstration of efficacy in rat spinal cord injury has not been reported, evidently because even relatively mild spinal cord contusions that produce only minor permanent locomotor disturbances abolish hind limb myoelectric motor evoked potentials (mMEPs). In this study, mMEPs were recorded acutely 25 days following graded thoracic spinal cord compression in rats. mMEP amplitudes were significantly enhanced by a single, 2 mg/kg i.v. dose of 4-AP. mMEPs were increased in all rats showing some evoked responses initially, and also in some animals which had no responses prior to treatment. 4-AP was further found to increase the maximum following frequency of mMEPs in both normal and injured rats from about 0.1 Hz to between 1 and 10 Hz. These data suggest that 4-AP might act by enhancing synaptic efficacy, as well as enhancing conduction in spinal axons whose myelination has been rendered dysfunctional by trauma.

Histological and functional evaluation of experimental spinal cord injury: evidence of a stepwise response to graded compression.

Most experimental spinal cord injury studies described to date have relied on a limited number of injury gradations, and have tacitly assumed that outcome (functional, histological, and/or neurophysiological) is a monotonically graded function of injury severity. In contrast, the present study provides evidence that functional and morphological outcome after spinal cord compression injury may occur in a discontinuous, non-graded manner in response to linearly graded injury levels. The thoracic spinal cord of adult rats was transiently compressed to thicknesses from 1.8 to 0.8 mm in 0.2 mm steps, or sham injury was administered. Open field motor behavior and segmental reflexes were evaluated up to 21 days post injury and correlated with histological measures and injury level. The highest correlation was between histological outcome and open field motor scores. Among the six injury groups, only three significantly different outcomes were apparent in the open field, reflex, and histological measures, consisting of the injury group pairs 1.8/1.6, 1.4/1.2, and 1.0/0.8 mm. At day 21, the 1.8/1.6 mm injury groups were also indistinguishable from the sham injury group. The implications of these findings in terms of therapeutic studies are discussed. Comparison of the temporal outcome patterns among contusion and compression injuries in rats and other species also revealed a significant species difference: a period of delayed or secondary functional loss reported in the guinea pig was not present in the rat.

Insulin-like growth factor-I prevents development of a vincristine neuropathy in mice.

Vincristine is a commonly used antitumor agent whose major dose-limiting side-effect is a mixed sensorimotor neuropathy. To assess whether insulin-like growth factor-I (IGF-I), a neurotrophic agent that supports the survival of motoneurons and enhances regeneration of motor and sensory neurons, could prevent the peripheral neuropathy produced by vincristine, mice were treated with both vincristine (1.7 mg/kg, i.p., 2 x /week) and/or IGF-I (0.3 or 1 mg/kg, s.c. daily) for 10 weeks. In mice treated with vincristine alone, there was evidence of a mixed sensorimotor neuropathy as indicated by changes in behavior, nerve conduction and histology. Caudal nerve conduction velocity was significantly slower in mice treated with vincristine alone as compared with vehicle-treated mice. Vincristine treatment alone also significantly increased hot-plate latencies and reduced gait support and stride length, but not toe spread distances. The effects of vincristine were accompanied by degeneration of sciatic nerve fibers and demyelination, indicating a peripheral neuropathy. IGF-I (1 mg/kg, s.c.) administered to vincristine-treated mice prevented the neurotoxic effects of vincristine as measured by nerve conduction, gait, response to noxious stimuli and nerve histology. At a lower dose of 0.3 mg/kg administered s.c., IGF-I partially ameliorated the neuropathy induced by vincristine as this dose only prevented the change in nerve conduction and hot-plate latencies. IGF-I administered alone had no effect on any of these parameters. These results suggest that IGF-I prevents both motor and sensory components of vincristine neuropathy and may be useful clinically in preventing the neuropathy induced by vincristine treatment.

Augmentation by 4-aminopyridine of vestibulospinal free fall responses in chronic spinal-injured cats.

This study examines the effect of the potassium channel blocker 4-aminopyridine (4-AP) on free fall responses (FFR) in the hindlimb muscles of chronically spinal injured cats. The thoracic spinal cord of 7 adult female cats was injured by a standardized contusion method. At 3-7 months post-injury the FFR in 6 hindlimb muscles was recorded electromyographically in each animal, under ketamine sedation. The normal short-latency response to a sudden drop was severely attenuated in all injured animals and practically undetectable in 2 cases. Within 15 min following intravenous administration of 1 mg/kg 4-AP, there was profound augmentation of the amplitude of the FFR and a tendency toward normalization of latency in all animals, though the normal amplitude range was not attained. The same 4-AP dose produced a relatively small increase of FFR amplitude in only 2 of 4 normal, uninjured animals tested. The data are consistent with previous observations that low doses of 4-AP restore conduction in some critically demyelinated axons, and provide support for the hypothesis that conduction block in surviving axons is responsible for a proportion of the dysfunction in chronic spinal injury. Augmentation of FFR in injured animals may also result partly from increased transmitter release in both spinal cord and periphery, due to the presynaptic effects of 4-AP.

Papulacandins, a new family of antibiotics with antifungal activity, I. Fermentation, isolation, chemical and biological characterization of papulacandins A, B, C, D and E.

Papulacandin, a new antibiotic complex, active against Candida albicans and several other yeasts, was isolated from a strain of Papularia sphaerosperma. The fermentation, isolation, physico-chemical properties and biological activity of the five structurally related papulacandins A, B, C, D and E are reported. Papulacandin B, the main component, was assigned the formula of C47H64O17.

Resistance of Escherichia coli to rifampicin and sorangicin A--a comparison.

Sorangicin A, a macrolide polyether antibiotic and the ansamycin antibiotic rifampicin inhibit DNA-dependent RNA polymerase to a similar extent. Resistance to sorangicin A is due to a mutation in the RNA polymerase which renders the enzyme less sensitive. Parallel investigations with rifampicin revealed partial cross-resistance, which was more marked in sorangicin A-resistant mutants than in rifampicin-resistant mutants.

Duramycins B and C, two new lanthionine containing antibiotics as inhibitors of phospholipase A2. Structural revision of duramycin and cinnamycin.

Duramycins B and C, two new lanthionine containing antibiotics, have been isolated from Streptoverticillium strain R2075 and Streptomyces griseoluteus (R2107). The known antibiotics duramycin and cinnamycin were reisolated from Streptoverticillium hachijoense (DSM 40114) and Streptomyces longisporoflavus (DSM 40165). The structures of these latter two compounds should be revised by changing amino acid residue 3 to glutamine and 17 to asparagine, respectively. Cinnamycin therefore seems to be identical to Ro 09-0198. Leucopeptin has been shown to be identical to duramycin. Physico-chemical data of these compounds provide evidence for a similar structure for all duramycin antibiotics. All compounds of this group inhibit human phospholipase A2 at a concentration of 10(-6) molar.

Nonlinear muscle recruitment during intramuscular and nerve stimulation.

Future progress in neuromuscular prostheses will depend on developing techniques for stimulating paralyzed muscle, especially utilizing neuromuscular stimulation. We have found nonlinear force versus stimulus amplitude characteristic (recruitment) curves in the gastrocnemius-soleus-plantaris muscle group of the cat in response to stimulation of the tibial nerve near the muscle entry point. Such response characteristics are undesirable in neuromuscular control systems. Nonlinear recruitment curves usually consisted of two regions in which force increased linearly with stimulus amplitude, separated by a "plateau" region in which force was relatively constant. The two linear regions were associated with activation of separate neuromuscular compartments (lateral or medial gastrocnemius, plantaris, soleus, or subdivisions of those muscles). When the stimulated myoelectric responses from these compartments were plotted versus stimulus amplitude, the region of recruitment between threshold and saturation often did not appreciably overlap for different compartments, suggesting that the axons innervating those compartments were physically segregated within the nerve from axons innervating other compartments. Correlation coefficients between force and stimulated myoelectric response were very high (up to R2 = 0.99) when using a composite curve produced by averaging myoelectric response curves recorded from each of the active compartments. By dividing the tibial nerve into its component bundles or fascicles and stimulating each in turn, it was possible to show that individual bundles innervate non-overlapping groups of muscle compartments, and that recruitment of the nerve bundles over different threshold ranges could account for the nonlinear force/stimulus response curves initially observed. The presence of separate innervation of muscles or compartments by fascicles should be an important factor in designing functional neuromuscular stimulation (FNS) systems.