Fuzzy logic: about the origins of fast ion dynamics in crystalline solids.

Nuclear magnetic resonance offers a wide range of tools to analyse ionic jump processes in crystalline and amorphous solids. Both high-resolution and time-domain [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] NMR helps throw light on the origins of rapid self-diffusion in materials being relevant for energy storage. It is well accepted that [Formula: see text] ions are subjected to extremely slow exchange processes in compounds with strong site preferences. The loss of this site preference may lead to rapid cation diffusion, as is also well known for glassy materials. Further examples that benefit from this effect include, e.g. cation-mixed, high-entropy fluorides [Formula: see text], Li-bearing garnets ([Formula: see text]) and thiophosphates such as [Formula: see text]. In non-equilibrium phases site disorder, polyhedra distortions, strain and the various types of defects will affect both the activation energy and the corresponding attempt frequencies. Whereas in [Formula: see text] ([Formula: see text]) cation mixing influences F anion dynamics, in [Formula: see text] ([Formula: see text]) the potential landscape can be manipulated by anion site disorder. On the other hand, in the mixed conductor [Formula: see text] cation-cation repulsions immediately lead to a boost in [Formula: see text] diffusivity at the early stages of chemical lithiation. Finally, rapid diffusion is also expected for materials that are able to guide the ions along (macroscopic) pathways with confined (or low-dimensional) dimensions, as is the case in layer-structured [Formula: see text] or [Formula: see text]. Diffusion on fractal systems complements this type of diffusion. This article is part of the Theo Murphy meeting issue 'Understanding fast-ion conduction in solid electrolytes'.

[Atlas fracture due to aneurysmal bone cyst after minor trauma]. / Fraktur des Atlas durch eine aneurysmatische Knochenzyste nach Bagatelltrauma.

Aneurysmal bone cysts predominantly occur in young adults and the long bones, the lumbar spine and the pelvis are mainly affected. This article presents the case of a 22-year-old woman with the very rare localization of an aneurysmal bone cyst of the atlas and an atlas fracture after a minor trauma. The initial radiological diagnosis was a suspicted aneurysmal bone cyst which was confirmed histologically. Due to the unstable fracture it was decided to carry out surgical treatment with occipitocervical stabilization in combination with a transoral bone graft. After a period of 11 months the fracture had completely healed and the implants were removed without any complications.

[A novel two-incision minimally invasive method for the treatment of anterior acetabular fractures]. / Der Zwei-Inzisions-Zugang in der Versorgung von Acetabulumfrakturen.

OBJECTIVES: To present a novel two-incision minimally invasive (TIMI) method for the treatment of anterior acetabular fractures. INTERVENTION: The first TIMI incision is performed using a pararectal approach at the level of the proximal third of the arcuate line of the ilium. After transection of the abdominal wall the iliac vessels are mobilized medially and the neuromuscular bundle laterally. The second approach lies above the medial pubic bone. The soft tissue is held back using a retraction system. After fracture reduction and fixation by isolated screws a conventional reconstruction plate is inserted for fracture neutralization. RESULTS: Since January 2008 we have performed the TIMI method in 88 cases with good results. Recently we have published the data of a first series with 26 patients that were seen at least 12 months after surgery. The mean operative time was 109 ± 30 min and all incisions showed primary healing. Postoperative radiological examination revealed an anatomic reduction in 20 fractures and a satisfactory reduction in 6. There were no local soft tissue complications and no revisions were needed. Follow-up examinations were performed after a minimum of 12 months in 19 patients (73%). The average Harris hip score (HHS) was 86.6 ± 8. Quality of life was comparable to control persons in the same age group. CONCLUSIONS: The TIMI approach represents a viable alternative to the ilioinguinal approach. Despite the limited number of incisions a comparable quality of fracture reduction is achieved. The authors believe this technique would be most useful in patients with a higher risk for postoperative soft tissue complications.

[Minimally invasive treatment of geriatric and osteoporotic femur fractures with polyaxial locking implants (NCB-DF®)]. / Minimalinvasive Versorgung geriatrischer und osteoporotischer Femurfrakturen mit polyaxial-winkelstabilem Implantat (NCB-DF®).

BACKGROUND: Periprosthetic femur fractures in elderly patients are a challenging surgical procedure. The aim of this study was a prospective evaluation of minimally invasive implantation of non-contact bridging (NCB-DF®) plates. PATIENTS AND METHODS: A total of 30 osteosynthesis procedures in 29 patients (average age 76 years and mean ASA 2.9) with complex femur fractures were registered, 19 fractures were periprosthetic and osteoporosis was present in 17 bones. In 25 patients a minimally invasive percutaneous procedure was performed using a standardized technique. An x-ray examination and clinical follow-up were performed after 6, 12 and 24 weeks. RESULTS: The early complications (14% in total) included 1 plate breakage after 16 weeks as well as 3 minor revisions for screw length correction. The x-ray follow-up after 24 weeks showed a secondary extension deficit of 10° and 15° in the knee joint in 2 patients, respectively. CONCLUSION: The NCB-DF® implantation using a standardized minimally invasive technique in periprosthetic femur fractures is a safe alternative in elderly patients. In this very sensitive population the early revision rate within the first 24 weeks is noticeable lower compared to similar procedures.

[The importance of CT angiography for screening supra-aortic vascular damage in severely injured patients]. / Bedeutung der CT-Angiographie zum Screening supraaortaler Gefässverletzungen beim Schwerverletzten.

PURPOSE: Traumatic injury of supra-aortic vessels remains a challenge in the initial diagnostics of severely injured patients. The presented prospective study analyzed the impact of multislice computed tomography angiography (CTA) as the primary diagnostic method. METHODS: Patients with the following criteria were included and screened for a dissection of the supra-aortic vessels: a) admission directly from the scene, b) resuscitation room treatment indicated by the official criteria of the DGU (German Society for the Surgery of Trauma), c) suspected blunt trauma to head or trunk as well as d) age over 16 years. RESULTS: During a period of 18 months 374 patients were treated for blunt trauma in the resuscitation room. In 176 cases CTA of the supra-aortic vessels was performed and pathological findings were observed in 16 patients. In 4 cases (2%) a traumatic dissection of supra-aortal vessels was diagnosed and confirmed by magnetic resonance imaging (MRI). All patients received heparin in a PTT effective dosage for 2 weeks and after rehabilitation there were no neurologic deficits. CONCLUSION: Traumatic supra-aortic dissection was found in 2% of cases in the presented study group. The mechanisms of injury were not distinct in this group. Essentially MSCT angiography screening was demonstrated to be a safe diagnostic tool.

[Volar locking compression plating versus dorsal plating for fractures of the distal radius: a prospective, randomized study]. / Volare winkelstabile vs. dorsale Plattenosteosynthese bei der distalen Radiusextensionsfraktur: Eine prospektive, randomisierte Untersuchung.

INTRODUCTION: This study investigated the radiographic and functional outcomes of two different methods for treating fractures of the distal part of the radius. PATIENTS AND METHODS: In a prospective controlled study patients with forearm fractures were randomized by age, handedness, and fracture type. RESULTS: The study included 120 patients, with a mean age of 66 years. Forty-nine percent of the fractures were extraarticular, and 51% were intraarticular. In the group treated with volar locking compression plates, six patients needed operative decompression of the median nerve and one needed reconstruction of the extensor pollicis longus (EPL) tendon. The group with dorsal plating had three complications requiring operative treatment: one deep infection, one dislocation of the plate, and one reconstruction of the EPL tendon. The radiological results for the Stewart 1 score showed 68% excellent results in volar locking compression plating compared with 57% in dorsal plating. Regarding functional outcome, 48% with volar plating showed excellent results compared with 22% with dorsal plating, as measured by the Stewart 2 score. CONCLUSION: Despite significant advantages of the volar locked compression plating, subjective satisfaction did not differ between the two groups.

One year after proximal or distal periprosthetic fracture of the femur -two conditions with divergent outcomes?

INTRODUCTION: Arthroplasty of the hip and knee is 1 of the 20 most frequent operations in Germany. Periprosthetic fracture is one of the most feared complications following primary or revision arthroplasty. Present publication aims to analyse differences between patients with periprosthetic fracture around total knee arthroplasty (PFTKA) and patients with periprosthetic fracture around total hip arthroplasty (PFTHA) concerning demographics, clinical course, complications and return to pre-fracture mobility. METHODS: Prospective single-centre observation study of periprosthetic femoral fractures with stable implants. Present subgroup analysis includes patients with PFTKA and PFTHA. All patients were treated with polyaxial angular stable plates using two standardized techniques: a minimally invasive percutaneous distal insertion technique and a mini-open technique. Data collection included implant- and operation-related information as well as demographics, clinical course, complications and return to pre-fracture mobility. Data were collected during a 12-month follow-up. RESULTS: We were able to analyse the data of 73 patients. The PFTKA group had 37 patients with a mean age of 76 ±â€¯10 years; 88% were female. After 1 year, 3 patients in this cohort had died; 68% of survivors had reached their pre-fracture mobility; 22% had undergone operative revisions for various reasons. The PFTHA cohort included 36 patients with a mean age of 80 ±â€¯13 years, 72% were female. After 1 year, 9 patients had died in this cohort, 42% of survivors had reached their pre-fracture mobility. Non-operative complications occurred for 16% in the PFTKA group and 64% in the PFTHA group (p < 0.001). 11% had undergone operative revisions for various reasons, among them, two cases of nonunion but no primary infection. CONCLUSION: On average, compared to the PFTHA patients, PFTKA patients were younger, underwent significantly lower rates of non-operative complications, had a tendency towards lower mortality, and returned to pre-fracture mobility at higher rates, although they tended to have more revisions when compared to treatment for PFTHA. Overall, when periprosthetic fractures of the femur were treated using polyaxial locking plate osteosynthesis, patients showed very low rates of nonunion and no primary infection.

Three-dimensional structure of glutathione S-transferase from Arabidopsis thaliana at 2.2 A resolution: structural characterization of herbicide-conjugating plant glutathione S-transferases and a novel active site architecture.

Glutathione S-transferases (GST) are a family of multifunctional enzymes involved in the metabolization of a broad variety of xenobiotics and reactive endogenous compounds. The interest in plant glutathione S-transferases may be attributed to their agronomic value, since it has been demonstrated that glutathione conjugation for a variety of herbicides is the major resistance and selectivity factor in plants. The three-dimensional structure of glutathione S-transferase from the plant Arabidopsis thaliana has been solved by multiple isomorphous replacement and multiwavelength anomalous dispersion techniques at 3 A resolution and refined to a final crystallographic R-factor of 17.5% using data from 8 to 2.2 A resolution. The enzyme forms a dimer of two identical subunits each consisting of 211 residues. Each subunit is characterized by the GST-typical modular structure with two spatially distinct domains. Domain I consists of a central four-stranded beta-sheet flanked on one side by two alpha-helices and on the other side by an irregular segment containing three short 3(10)-helices, while domain II is entirely helical. The dimeric molecule is globular with a prominent large cavity formed between the two subunits. The active site is located in a cleft situated between domains I and II and each subunit binds two molecules of a competitive inhibitor S-hexylglutathione. Both hexyl moieties are oriented parallel and fill the H-subsite of the enzyme's active site. The glutathione peptide of one inhibitor, termed productive binding, occupies the G-subsite with multiple interactions similar to those observed for other glutathione S-transferases, while the glutathione backbone of the second inhibitor, termed unproductive binding, exhibits only weak interactions mediated by two polar contacts. A most striking difference from the mammalian glutathione S-transferases, which share a conserved catalytic tyrosine residue, is the lack of this tyrosine in the active site of the plant glutathione S-transferase.

[Determination of cartilage thickness in the ankle joint. an MRT (1.5)-anatomical comparative study]. / Bestimmung der Knorpeldicke am oberen Sprunggelenk. Eine MRT (1,5T)-anatomische Vergleichsstudie.

PURPOSE: The aim of this study was to evaluate the accuracy of MRI in the measurement of cartilage thickness of the ankle joint in comparison to pathologic and histologic specimens. PATIENTS AND METHODS: The ankle joints of four fresh cadaver feet were imaged on a 1.5T MR-unit in the coronal plane. Standard T1-weighted spin echo (SE) and a T1-weighted 3D-GE (FLASH-3D) sequence with fat saturation were applied. Following MR imaging, the talus was explanted and cut parallel to the MR images for macroscopic evaluation and histologic specimens were prepared. MRI measurements of the cartilage thickness of the talus were carried out in two ways: without and with consideration of a transition zone of intermediate signal intensity between hyperintense cartilage and hypointense cortical bone. The data were compared with the anatomic specimens as the gold standard expressing the difference as a percentage value. On histologic specimens thickness of deep calcified cartilage layer was measured. RESULTS: Measurements without the transition zone showed a mean underestimation of talus cartilage thickness of 46.8% (41.3-52.1) for T1-SE and 47.5% (43.1-52.1) for fat saturated FLASH-3D images. Considering the transition zone the mean values were 25.0% (23.1-26.2) and 14.1% (6.7-21.5). The histologic specimens showed a three-fold increase of thickness of deep calcified cartilage layer. CONCLUSIONS: Measurements of the cartilage layer of the ankle joint on MR images are only accurate if the transition zone (calcified cartilage layer) is considered and the optimal pulse sequence (FLASH-3D-fat-sat) is applied.

Acquired hallux varus and clinical tolerability.

This retrospective study was undertaken to determine the long-term clinical problems, residual disability, and need for further surgery in patients with iatrogenic hallux varus. Between 1975 and 1985, in 16 (19 feet) of 83 patients who underwent foot surgery for hallux valgus or metatarsus primus varus, hallux varus deformity was noted at 1-year follow-up on dorsoplantar roentgenograms obtained with the patients bearing weight. Thirteen of those patients (16 feet) were reexamined at an average of 18.3 years (220 months) after surgery. The average hallux varus deformity in this group was 10.1 degrees. Eleven patients (12 feet) rated their results as excellent. The average hallux metatarsophalangeal interphalangeal score for all patients was 91.5 points. Only those with extreme hallux varus deformity were dissatisfied or required further surgery.

Comparison of the results of the Weil and Helal osteotomies for the treatment of metatarsalgia secondary to dislocation of the lesser metatarsophalangeal joints.

We retrospectively reviewed the outcome of 30 patients who were treated surgically for metatarsalgia resulting from dislocation of one or more lesser metatarsophalangeal (MTP) joints. We used two treatments, including an osteotomy of the metatarsal head (Weil osteotomy, N = 15) or an osteotomy of the metatarsal shaft (Helal osteotomy, N = 15). Before surgery, all patients had been treated with various nonoperative modalities for a minimum of 6 months. Between 1991 and 1993, 15 consecutive patients underwent a Helal osteotomy (22 metatarsals), and 15 consecutive patients were subsequently treated between 1994 and 1995 with a Weil osteotomy (25 metatarsals). All patients were evaluated clinically and radiographically at a mean follow-up period of 22 months (range, 12-39 months), noting especially persistent subluxation or dislocation, recurrent metatarsalgia, and transfer lesions. Patients managed with a Weil osteotomy had significantly higher satisfaction (P = 0.049), lower incidence of recurrent metatarsalgia (0 vs. 27%, P = 0.107), and fewer transfer lesions (0 vs. 41%, P = < 0.001) than those managed with a Helal osteotomy. Furthermore, those managed with the Weil procedure had a higher percentage of radiographic reduction and maintenance of the MTP joint dislocation (21 of 25, 84%; vs. 8 of 22, 36%; P = 0.002) than those managed with the Helal procedure. In the Weil group, there was also no malunion or pseudoarthrosis; in the Helal group there were five malunions and three pseudoarthroses. Although the follow-up period for the Weil osteotomy (15 months) was shorter than that for the Helal osteotomy (26 months), the former group had higher American Orthopaedic Foot and Ankle Society forefoot scores, which were significantly different from the results attained with the Helal osteotomy. A telephone update was performed on the Weil osteotomy group at an average of 27 months postsurgery, and no patient had experienced changes since the clinical follow-up. We concluded that the Weil procedure is a satisfactory method for correcting metatarsalgia caused by dislocation of the MTP joint and that, because of the high complication rate, the Helal osteotomy is not an acceptable procedure for correcting this condition.

Helal metatarsal osteotomy for the treatment of metatarsalgia: a critical analysis of results.

We reviewed the results of treatment of 114 feet in 96 patients with pressure metatarsalgia treated with a metatarsal osteotomy performed according to the technique of Helal. Clinical examination was performed according to a standardized evaluation questionnaire using the American Orthopaedic Foot and Ankle Society Lesser Metatarsophalangeal-Interphalangeal Scale. The results were correlated with number of metatarsal osteotomies, the length of the follow up, the age of the patient, and type of additional procedures performed. Sixty-one percent of the patients rated the operation as excellent or good. Patient age and number of osteotomies did not influence the results; however, the length of time following surgery and associated Keller-Brandes resection arthroplasty influenced the outcome negatively. There was a high incidence of increased transfer of weight to adjacent metatarsals. We concluded that the Helal type metatarsal osteotomy is unlikely to predictably achieve symptom relief over a long period.

[Injuries- and frequency of complaints in competitive tennis- and leisure sports]. / Verletzungs- und Beschwerdehäufigkeit im Tennisleistungs- und Breitensport.

Tennis is one of the most popular sporting activities in Germany and worldwide. According to this fact injuries and complaints associated with this sport are common in tennis players. Here a retrospective analysis was undertaken in 60 tennis players with and 50 tennis players without tournament experience. Injuries were seen in all players. The most common lesions were blisters, sunburn and abrasions (65.5 %) followed by cramps (51.8 %), strains (35.5 %) and sprains (25.5 %). More severe injuries like meniscal lesions or ruptures of the cruciate- and ankle-ligaments or the achilles tendon were found in 2 % to 4 %. Fractures were not seen in this study. The majority of tennis injuries occurred in the lower extremity (182 vs. 62) whereas chronic complaints domain in the upper extremity (38/91). Most of the injuries and complaints have been treated conservatively with good results. Only 3.3 % of all acute and 2.2 % of the chronic lesions were treated by surgical intervention.

NCB-plating in the treatment of geriatric and periprosthetic femoral fractures.

BACKGROUND: The aim of this study is the presentation of the polyaxial locking NCB-plate in the treatment of femoral fractures, especially in elderly patients and in proximity of a prosthetic implant. The reduction and fixation of these fractures is a challenging surgical procedure with high complication rates reported up to 40%. PATIENTS AND METHODS: A total of 72 patients with femoral fractures had polyaxial locking plate osteosynthesis. Indications included fractures of the shaft and around an implant. Concerning surgical procedures, three different standardized techniques were performed: (1) minimally invasive with percutaneous distal insertion using a targeting device; (2) mini-open with additional cerclage wire via the same approach and (3) a conventional open reduction and internal fixation. Data collection included intraoperative data and early complications at 6, 24 and 52 weeks. Fifty-two patients had an implant or prosthesis in situ. Thirty-three patients were treated by technique (1), 32 patients had mini-open surgery and seven patients conventional open surgery. RESULTS: Thirty-nine patients attended clinical follow-up after 52 weeks. Twenty-two patients were interviewed by telephone, two were untraceable and nine patients had died. Bony consolidation without secondary loss of reduction was confirmed after 52 weeks in all patients but two. Plate breakage occurred in these two at 25 and 31 weeks after surgery due to non-union. Implant related complications (17% in total) lead to surgical revision in five other cases: two deep wound infections as well as three minor revisions. When itemizing complications according to surgical technique used, most major complications occurred following open surgery. CONCLUSION: The availability of polyaxial locking implants widened the range of indications for plate fixation in femoral fractures. The advantages of the polyaxial locking implant combined with minimally invasive surgical technique contribute to successful management of this population category. Early revision rate is noticeably lower compared to similar procedures. LEVEL OF EVIDENCE: IV retrospective series.

Emergency Transfusion Score (ETS): a useful instrument for prediction of blood transfusion requirement in severely injured patients.

BACKGROUND: Efficient blood transfusion management presents an ongoing challenge for many trauma centers. We present the Emergency Transfusion Score (ETS), a measure that may allow important time and cost savings in the treatment of severely injured patients in the Emergency Room (ER). METHODS: The ETS includes the parameters low blood pressure, free fluid on ultrasound, clinical instability of the pelvic ring, age, admission from the scene, and trauma mechanism. An ETS >or= 3 indicates a transfusion probability of 5% and was set as the cut-off to order blood products (10 packed red blood cells [PRBC]/10 fresh frozen plasma [FFP]). RESULTS: A total of 481 patients requiring trauma team activation (ISS 18 +/-18; 7/03-12/04) were prospectively included. The ETS was < 3 in 306 patients (64%) and >or= 3 in 175 subjects (36%). Some 40 patients (8.3%) received blood (8 +/- 8 PRBC) after 23 +/- 9 min during ER treatment, and 39 of these patients had an ETS of >or= 3 (5.4 +/- 1.5 points). Sensitivity of the ETS was 97.5%; specificity, 68%. Positive predictive value of the ETS was 0.222; negative predictive value, 0.998. CONCLUSIONS: (1) The ETS is a safe and highly sensitive tool with which to detect severely injured patients in need of blood products. (2) The ETS is highly predictive for patients not in need of PRBC (negative predictive value 0.998) and helps to avoid unnecessary cross-matching and transport. (3) After implementation of the ETS, a sum of about 109,296 USD was saved per year by reducing the costs for cross-matching, transportation, and wasted blood products.

[Penetrating gunshot injuries to the head and brain. Diagnosis, management and prognosis]. / Penetrierende Schädel-Hirn-Verletzungen durch Schusswaffen. Diagnostik, Behandlungsmanagement und Prognose.

Gunshot injuries to the head and brain are rare in Germany and the rest of western Europe. With the relatively low number of these injuries here, there are no standard methods of diagnosis and management, and there is some controversy over both. Quite a high proportion of such injuries result from suicide attempts and accidents. The main diagnostic procedure available is computed tomography of the head with contrast medium; in certain cases MRI is indicated. The operative management depends on the extent and prognosis of the injury; a ventricular drain is probably indicated in most cases. Debridement of the bullet's path and removal of the projectile are more controversial. Mortality is extremely high after such injuries; if the victim does survive the prognosis is comparable to that following closed cranial injuries.

Photoaffinity labeling of Arabidopsis thaliana plasma membrane vesicles by 5-azido-[7-3H]indole-3-acetic acid: identification of a glutathione S-transferase.

We used 5-azido-[7-3H]indole-3-acetic acid (5-azido-[7-3H]IAA), a photoaffinity analogue of the plant hormone indole-3-acetic acid (IAA), to search for auxin-binding proteins in Arabidopsis thaliana membranes. We identified an auxin-binding protein with a molecular mass of 24 kDa (Atpm24) in microsomes as well as in plasma membrane vesicles. Atpm24 was solubilized by 1% Triton X-100 and partially purified. A cDNA clone (Atpm24.1) corresponding to Atpm24 was isolated. The amino acid sequence predicted from the Atpm24.1 cDNA contains 212 amino acid residues with a relative molecular mass of 24,128 Da. Data base searches revealed that the predicted protein has homology to glutathione S-transferases (GSTs; EC 2.5.1.18). When Atpm24.1 was expressed in Escherichia coli, we found a high level of GST activity in the bacterial extracts. We have analyzed the substrate specificity of this protein and found that cumene hydroperoxide and trans-stilbene oxide but not trans-cinnamic acid or IAA-CoA were substrates. A role for this GST in physiological processes of plants is discussed.

Identification of a 23 kDa protein from maize photoaffinity-labelled with 5-azido-[7-3H]indol-3-ylacetic acid.

A 23 kDa protein (p23) was identified in microsomal extracts from maize coleoptiles by photoaffinity labelling with 5-azido-[7-3H]indol-3-ylacetic acid ([3H]N3IAA). Labelling of p23 was blocked by unlabelled IAA, N3IAA, indol-3-ylbutyric acid and indol-3-yl-lactate. In addition, labelling was efficiently decreased by tryptophan, as well as by the scavenger p-aminobenzoic acid. Labelling was, however, not affected by synthetic auxins such as 1-naphthylacetic acid or 2,4-dichlorophenoxyacetic acid. Competition data suggest that the label was probably bound via the indole ring, and hence labelling was not specific for auxins. The 23 kDa protein was solubilized from crude microsomes by extraction with Triton X-100 and purified to homogeneity by ion-exchange, size-exclusion and reversed-phase chromatography. After electroblotting, the amino acid sequences of the p23 N-terminus as well as the several tryptic peptides were obtained. Database comparisons revealed sequence identity with a maize manganese superoxide dismutase. We conclude that photoaffinity labelling of p23 was pseudo-affinity, and therefore the binding site for IAA is not specific.

[The accuracy of palpation from orientation points for the navigated implantation of knee prostheses]. / Antastgenauigkeit von Orientierungspunkten bei navigierter Implantation von Knieendoprothesen.

AIMS: Cinematic and pointing procedures are used for non-image based navigated implantation during total knee replacement. Pointing procedures require an exact knowledge of the landmarks. In this anatomical study, landmarks are defined and repeatedly referenced. Precision and reproducibility are evaluated by means of an inter- and an intra-observer study. The axes of the femur and tibia are calculated using the landmarks. MATERIAL AND METHODS: The specific landmarks of 30 femurs and 27 tibias were palpated by three surgeons and digitised by means of a photogrammetric system, as used intra-operatively. The recorded data were statistically evaluated. RESULTS: The specific landmarks can be referenced with great precision. The vectors that influence the implant position show a mean femoral deviation of 0.9 mm and a mean tibial deviation of 1.0 mm. The repeating accuracy of every observer was 1.5 mm femoral and 1.0 mm tibial. The calculated long axes at the femur and tibia thus reach a precision of 0.1 degrees (min.-max.: 0-0.9 degrees) at the femur and 0.2 degrees (.0-1.1 degrees) at the tibia. The short axes at the distal femur and proximal tibia exhibit an average deviation of from 0.7 degrees to 1.9 degrees (0-11.3 degrees). CONCLUSION: Long axes (mechanical axes) can be determined exactly but the precision of the short axes (rotational axes) is unsatisfactory, although palpation of landmarks was accurate. Therefore, palpation of more than one rotational axis at the femur and tibia is mandatory and should be visualized on the monitor during surgery.

Fracture of the anterior superior process of the calcaneus: an often misdiagnosed fracture.

Fracture of the anterior superior process of the calcaneus has been considered an unusual injury. Following a sudden twist there is immediate pain on the outer aspect of the mid-portion of the foot and discomfort on weight-bearing. Three mechanisms of injury have been reported to cause the fracture. The diagnosis is often missed, and prolonged disability and local pain at the calcaneocuboid joint deserve further consideration. Oblique X-rays of the foot are helpful to visualize the fracture. Type III fractures may cause cartilage lesions and arthrosis; therefore, one should not wait long before excision or refixation of the fragment.