[Minimally invasive proximal hamstring insertion repair]. / Minimal-invasive endoskopische Rekonstruktion der proximalen Hamstring-Insertion.

OBJECTIVE: Minimally invasive endoscopic reconstruction of avulsion injuries of the proximal hamstring insertion to prevent persistent weakness and pain. INDICATIONS: Fresh retracted 2­ and 3­tendon avulsion injuries of the proximal hamstring insertion. Unsuccessful conservative therapy of less retracted injuries. Painful chronic partial lesions of the proximal hamstring insertion. CONTRAINDICATIONS: Major comorbidities with an increased surgical risk, older patients with low functional demands. Chronic injuries without functional deficits. SURGICAL TECHNIQUE: Endoscopic refixation using suture anchors after freshening the footprint on the tuber ischiadicum. Visualization of the sciatic nerve to ensure its protection. POSTOPERATIVE MANAGEMENT: Partial loading with a knee brace for strict prevention of combined knee extension and hip flexion for 4-6 weeks. Start of active exercise and stretching 8 weeks postoperatively. RESULTS: From 2014-2016, 12 patients were treated with an endoscopic reconstruction of the proximal hamstring insertion. After a mean follow-up of 25 months (range 16-34 months), an average visual analog scale (VAS) of 0 (range 0-2) and an average subjective assessment of function (Subjective Hip Value) of 94% (range 80-100%) were found. No neurovascular complications were seen in our collective, in particular no evidence of hypesthesia in the area of the posterior femoral cutaneous nerve. All patients were able to return to their original level of activity (Tegner Activity Scale 5.2 preoperatively vs. 5.2 postoperatively), while the average time until return to sport was 6.5 months (range 3-12 months). All patients were able to return to their original occupation.

[Open repair of gluteus medius and minimus tendons tears with double-row technique : Clinical and radiological results]. / Offene Refixation von Gluteus medius und minimus in Double-Row-Technik : Klinische und radiologische Ergebnisse.

BACKGROUND: Operative refixation is a new therapeutic option in cases of failed conservative treatment for trochanteric pain syndrome (TPS) and lesions of the hip abductors in magnetic resonance imaging (MRI). OBJECTIVE: Evaluation of the clinical and radiological results after open gluteus medius and minimus tendon reconstruction with a double-row technique was carried out. MATERIAL AND METHODS: Patients with failed conservative treatment for TPS and confirmed lesions of the hip abductors in MRI were treated by open hip abductor tendon reconstruction with a double-row technique. The patients were evaluated preoperatively and postoperatively (minimum follow-up 12 months) using the modified Harris hip score (mHHS) and a subjective score (subjective hip value, SHV). Preoperative and postoperative MRI evaluation included measurement of hip abductor muscle diameter and cross-sectional area as well as fatty degeneration. RESULTS: In this study 12 consecutive cases of open reconstruction of the hip abductor tendons were included. There was a significant improvement in the mHHS. In one case the patient showed an atraumatic rupture in the proximal anchor row. The MRI showed a significant improvement in muscle diameter and cross-sectional area for the gluteus medius muscle of the affected and the contralateral side, while the degree of fatty degeneration did not improve. The fatty degeneration showed a significant correlation with the postoperative results in the mHHS and the SHV. CONCLUSION: Operative reconstruction of lesions in the hip abductor tendons is a therapy option with significant improvement of patient satisfaction and functional scores as well as muscle diameter and cross-sectional area for the gluteus medius. The degree of fatty degeneration and possible differential diagnoses need to be taken into consideration.

[Osseous tuberculosis as a rare differential diagnosis of femoral head necrosis]. / Ossäre Tuberkulose als seltene Differenzialdiagnose der Femurkopfnekrose.

BACKGROUND: We report on a 60-year-old immunocompetent German male patient without risk factors, who had been suffering from pain in the right hip for 8 months. DIAGNOSTICS: Radiographs showed destruction of the femoral head with a collapse of the main weight-bearing area, which was interpreted as femoral head necrosis. THERAPY: A cement-free total hip prosthesis was then implanted. The femoral head was sent for routine histological analysis and PCR amplification yielded a positive result for Mycobacterium tuberculosis complex DNA, leading to immediate guideline-based tuberculostatic treatment. CONCLUSION: Tuberculosis should be considered as a differential diagnosis in the case of destruction of the femoral head, especially in immunocompromised patients, patients with a foreign background or destructive osteoarthritis of the hip with an atypical course. Antibiotic treatment is necessary postoperatively. Under this therapy, a good clinical outcome can be expected comparable to that achieved in patients with primary osteoarthritis without infection.

[Arthroscopic correction of extra-articular subspinal impingement in the hip joint]. / Arthroskopische Korrektur des extraartikulären Subspine-Impingements am Hüftgelenk.

We report the case of symptomatic extra-articular subspinal impingement in the hip joint caused by a pathological contact between the anterior inferior iliac spine (AIIS) and the femoral neck. A 28-year-old patient presented with activity-related inguinal pain on the right side and a positive anterior impingement test in the clinical examination. Radiological examinations revealed a hypertrophic AIIS with caudal extension below the acetabulum. After a positive injection test confirmed the AIIS as the origin of the pain, arthroscopic correction with partial resection of the AIIS was performed resulting in significant pain relief and improved range of motion.

[Musculoskeletal load analysis. A biomechanical explanation for clinical results--and more?]. / Muskuloskeletale Belastungsanalysen. Biomechanische Erklärung klinischer Resultate--und mehr?

Mechanical loading of the lower extremities due to muscle and joint contact forces plays an important role in orthopaedic and trauma surgery. Detailed, patient specific information on the in vivo forces and their distribution is, however, currently not readily available to the surgeon in clinical routine. The goal of this study was to elucidate the relationship between the position of the cup and the musculoskeletal loading conditions at the hip using validated analyses, and further, to evaluate the predictions of the biomechanical conditions against the results of a clinical study. The results indicate that restoring the anatomical hip centre to its anatomical mediolateral position could help to reduce joint loads and add to the longevity of the reconstruction. The routine use of validated analyses of musculoskeletal loading conditions, such as in the presented example using standardised pre-operative planning and sound intra-operative decision support systems, could contribute to securing a high standard in patient treatment.

[Histopathological diagnostics in endoprosthesis loosening]. / Histopathologische Diagnostik der Endoprothesenlockerung.

The implantation of total joint endoprostheses has become a routine procedure, being executed about 1.5 million times per year worldwide. The indications are osteoarthritis, rheumatic diseases, trauma and bone neoplasia. However, about 5-12% of patients develop pain and impaired function of the endoprosthesis within 10 years, necessitating revision surgery. During this operation, the so-called periprosthetic membrane between bone and prosthesis is removed. This connective tissue membrane has a pathogenetic impact on the loosening process and can be evaluated by histopathology. This article aims at elucidating the defined histomorphological criteria for the standardized diagnostics of periprosthetic membranes using a recently established classification system.

Proposal for a histopathological consensus classification of the periprosthetic interface membrane.

AIMS: The introduction of clearly defined histopathological criteria for a standardised evaluation of the periprosthetic membrane, which can appear in cases of total joint arthroplasty revision surgery. METHODS: Based on histomorphological criteria, four types of periprosthetic membrane were defined: wear particle induced type (detection of foreign body particles; macrophages and multinucleated giant cells occupy at least 20% of the area; type I); infectious type (granulation tissue with neutrophilic granulocytes, plasma cells and few, if any, wear particles; type II); combined type (aspects of type I and type II occur simultaneously; type III); and indeterminate type (neither criteria for type I nor type II are fulfilled; type IV). The periprosthetic membranes of 370 patients (217 women, 153 men; mean age 67.6 years, mean period until revision surgery 7.4 years) were analysed according to the defined criteria. RESULTS: Frequency of histopathological membrane types was: type I 54.3%, type II 19.7%, type III 5.4%, type IV 15.4%, and not assessable 5.1%. The mean period between primary arthroplasty and revision surgery was 10.1 years for type I, 3.2 years for type II, 4.5 years for type III and 5.4 years for type IV. The correlation between histopathological and microbiological diagnosis was high (89.7%), and the inter-observer reproducibility sufficient (85%). CONCLUSION: The classification proposed enables standardised typing of periprosthetic membranes and may serve as a tool for further research on the pathogenesis of the loosening of total joint replacement. The study highlights the importance of non-infectious, non-particle induced loosening of prosthetic devices in orthopaedic surgery (membrane type IV), which was observed in 15.4% of patients.

Endothelin-1 is secreted after total knee arthroplasty regardless of the use of a tourniquet.

Early infections and wound healing disorders after implantation of a total knee replacement occur regardless of the intraoperative use of a tourniquet. The biochemical regulatory processes responsible for the disturbances in microcirculation and thus the potential therapeutic options have yet to be elucidated. The hypothesis of the present paper was that endothelin-1 (ET-1), a mediator of microcirculation disturbances in parenchymatous organs, also is released after major operations on peripheral joints. The concentration of ET-1 in the plasma was determined preoperatively and at 10 postoperative time points (5 min-48 h) with (group A, n=10) and without the use of a tourniquet (group B, n=10). The ET-1 concentration achieved its maximum 6h after opening the tourniquet, which corresponded to 3.3 times the preoperative value. Without a tourniquet, the concentration maximum (2.9 times the baseline value) was achieved already 1.5 h after the end of the operation. However, the total amount of ET-1 secreted over 24 h was identical in both groups (p>0.5). We conclude that the tissue hypoxia resulting from the use of a tourniquet modulates ET-1 secretion, but that traumatization during the operation has a much stronger influence on the total amount secreted. ET-1 antagonists thus should be discussed for the drug prophylaxis of wound healing disorders, regardless of the use of a tourniquet.

[Proposal for the classification of the periprosthetic membrane from loosened hip and knee endoprostheses]. / Vorschlag für eine Konsensus-Klassifikation der periprothetischen Membran gelockerter Hüft- und Knieendoprothesen.

After 10 years, loosening of total joint endoprostheses occurs in about 3 to 10 percent of all patients, requiring elaborate revision surgery. A periprosthetic membrane is routinely found between bone and loosened prosthesis. Further histomorphological examination allows determination of the etiology of the loosening process. Aim of this study is the introduction of clearly defined histopathological criteria for a standardized evaluation of the periprosthetic membrane. Based on histomorphological criteria and polarized light microscopy, four types of the periprosthetic membrane were defined: periprosthetic membrane of wear particle type (type I), periprosthetic membrane of infectious type (type II), periprosthetic membrane of combined type (type III), periprosthetic membrane of indifferent type (type IV). Periprosthetic membranes of 268 patients were analyzed according to the defined criteria. The correlation between histopathological and microbiological diagnosis was high (89%, p<0,001), the inter-observer reproducibility was sufficient (95%). This classification system enables a standardized diagnostic procedure and therefore is a basis for further studies concerning the etiology of and pathogenesis of prosthesis loosening.

Absence of cross-modal reorganization in the primary auditory cortex of congenitally deaf cats.

To investigate possible cross-modal reorganization of the primary auditory cortex (field A1) in congenitally deaf cats, after years of auditory deprivation, multiunit activity and local field potentials were recorded in lightly anesthetized animals and compared with responses obtained in hearing cats. Local field potentials were also used for current source-density analyses. For visual stimulation, phase-reversal gratings of three to five different spatial frequencies and three to five different orientations were presented at the point of central vision. Peripheral visual field was tested using hand-held stimuli (light bar-shaped stimulus of different orientations, moved in different directions and flashed) typically used for neurophysiological characterization of visual fields. From 200 multiunit recordings, no response to visual stimuli could be found in A1 of any of the investigated animals. Using the current source-density analysis of local field potentials, no local generators of field potentials could be found within A1, despite of the presence of small local field potentials. No multiunit responses to somatosensory stimulation (whiskers, face, pinna, head, neck, all paws, back, tail) could be obtained. In conclusion, there were no indications for a cross-modal reorganization (visual, somatosensory) of area A1 in congenitally deaf cats.

Conditions of perceptual selection and suppression during interocular rivalry in strabismic and normal cats.

Presenting the two eyes with incongruent stimuli leads to the phenomenon of interocular rivalry. At any given time, one of the stimuli is perceptually suppressed in order to avoid double vision. In squinting subjects, rivalry occurs permanently also for congruent stimuli because of developmental rearrangement of cortical circuitry. In this study, we have investigated the dynamics and stimulus dependence of rivalry in six esotropic, four exotropic and three non-strabismic cats. As an indicator for perception, we used optokinetic nystagmus that was induced by moving gratings. The esotropic cats were tested for their visual acuity by means of a jumping stand procedure. The results show that one eye can dominate perception even if both eyes have equal visual acuity and are presented with stimuli of equal contrast. Strong eye dominance asymmetry was found in all but one of the tested cats. Notably, all three of the normal cats showed a clear asymmetry in perceptual selection. Measurements with varying contrast and velocity of the stimuli revealed that the influence of these parameters on perceptual selection was independent of the presence of strabismus. In all cats, the time during which a given eye dominated perception increased with the contrast and decreases with the velocity of the stimulus presented to this eye.

Male polymorphism in Limia perugiae (Pisces: Poeciliidae).

The male-polymorphic poeciliid fish, Limia perugiae, a small teleostean endemic to the southeast of the Caribbean island Hispañola, consists of three male size morphs with uniform females. Large males differentiate at a size varying between 25 and 38 mm; intermediate males, between 21 and 25 mm. Under competition, large males exhibit an elaborate courtship display, whereas small males show only a sneak-chase behavior. Intermediate males adapt their tactics to the respective competitors. However, all male morphs can switch from courtship display to sneak-chase behavior. In large mating groups with four males of different size and five or six virgin females, large dominant alpha-males as well as small subordinate delta-males did not produce any offspring. Unexpectedly, all progeny were sired exclusively by the intermediate subordinate beta- and gamma-males. Breeding experiments with the three male morphs can best be explained by a model of Y-linked genes for small and large size which are both suspended by the activity of an autosomal recessive repressor responsible for the development of intermediate males. The dominant allele of the recessive repressor, in either its homoorits heterozygous state, activates the Y-chromosomal genes for large or small size, respectively. Accordingly, intermediate males may produce male offspring of all size classes, depending on the presence of either the Y-linked gene or the autosomal repressor.

Reproductive failure of dominant males in the poeciliid fish Limia perugiae determined by DNA fingerprinting.

Hierarchical structures among male individuals in a population are frequently reflected in differences in aggressive and reproductive behavior and access to the females. In general, social dominance requires large investments, which in turn then may have to be compensated for by high reproductive success. However, this hypothesis has so far only been sufficiently tested in small mating groups (one or two males with one or two females) due to the difficulties of determining paternity by conventional methods. DNA fingerprinting overcomes these problems by offering the possibility to determine genetic relationships and mating patterns within larger groups [Burke, T. (1989) Trends Ecol. Evol. 4, 139-144]. We show here that in the poeciliid fish Limia perugiae, in small mating groups the dominant male has a mating success of 100%, whereas in larger groups its contribution to the offspring unexpectedly drops to zero.

Mutational changes of quantitative morphological traits in the convict cichlid (Cichlasoma nigrofasciatum Guenther) after irradiation of parental spermatogonia and oogonia with different doses of X-rays.

10 continuous and 6 discrete variables of body dimensions as well as 16 proportions calculated from them were determined in postirradiation F1 convict cichlid fish (Cichlasoma nigrofasciatum) which were derived from spermatogonia and oogonia both exposed to either 0 (controls), 250, 500, 750, 1000, or 2000 R of X-rays. While no interactions with sex or radiation dose were found, clear dosage effects and some sex effects occurred. The highest response for almost all quantitative traits examined as well as for variants of coloration or of vertebral aberrations appeared after 250 R to both parental germ cells. The lowest effectiveness was observed for almost all characters under investigation after 0 and 500 R. Accordingly, the largest difference between the 6 different treatment groups was found between 250 and 500 R, followed by 250 and 0, 250 and 1000, and 250 and 750 R to parental gonia. The present finding on the alterations of quantitative morphological traits completely corresponds to the changes of intraspecific aggressiveness as found for the same individual fish in a previous study thus confirming the complete congruence of the mutational response of quantitative morphological characters with that of behavioral traits to ionizing radiation.

[Quantitative analysis of melanoma growth in tumorous fish of the genus Xiphophorus after partial-body X-irradiation with therapeutic doses (author's transl)]. / Quantitativer Verlauf des Melanomwachstums bei Tumorfischen der Gattung Xiphophorus nach Röntgenteilkörperbestrahlung mit therapeutischen Dosen.

Hereditary melanomas in Xiphophorus helleri, caused by the spotted dorsal gene, Sd, and its modifiers, have arisen by introgressive hybridization of X. maculatus X X. helleri-hybrids with X. helleri. 7 of those melanotic poeciliid fish had been X-irradiated, 10 tumorous sibs from the same brood were kept as controls. The total X-ray dose of 9000 R was fractionated into partial doses of 5000 R and 4000 R, respectively. Only the melanomatous regions of the caudal peduncle and those of the dorsal part of the body, the dorsal and caudal fins included, were irradiated. The rest of the trunk was shielded with lead against radiation. The teleosteans were 162 days old when irradiated for the first time; the second exposure followed 193 days later. In intervals of 14 or 21 days, the animals had been photographed, and the melanotic areas of the enlarged prints had been determined by planimetrical measuring. After this, they were calculated as percent of the total body surface, both with and without the dorsal fin area. There was a significant regression of melanoma growth in irradiated fish.