[The chronic central fracture dislocation of the hip]

The acetabulum fracture with chronic dislocation of the femoral head is relatively uncommon. Due to complex morphology and bone defect of the acetabular dome, stable internal fixation is difficult. Primary total hip arthroplasty represents an alternative treatment. We report the case of a 66-year-old patient with a 3-month history of acetabular fracture with central dislocation of the femoral head. The patient was treated with cemented total hip arthroplasty and cancellous bone grafting of the central dome defect for stable cup fixation.

Membrane Binding of Twin Arginine Preproteins as an Early Step in Translocation

The twin arginine transport (Tat) system translocates folded proteins across the bacterial inner membrane. Transport substrates are recognized by means of evolutionarily well-conserved N-terminal signal peptides. The precise role of signal peptides in the actual transport process is not yet fully understood. Potentially, much insight into the molecular details of the transport process could be gained from step-by-step in vitro experiments under controlled conditions. Here, we employ purified preproteins to study their interaction with the phospholipid membrane by using surface plasmon resonance spectroscopy. It turns out that preproteins interact tightly with a model membrane consisting of only phospholipids. This interaction, which is stabilized by both electrostatic and hydrophobic contributions, appears to constitute an early step in protein translocation by the Tat system.

[A bilaterally dislocated intraarticular calcaneus fracture in a 13-year old boy]

Bilaterally dislocated intraarticular calcaneus fractures in childhood are rare. This case report shows that adequate preoperative tissue management, open anatomical reduction, and lateral plate osteosynthesis by an experienced surgeon according to the principles of adult surgery achieve a good functional result.

[Injuries of the elbow joint]

Injuries of the elbow joint increase along with increased athletic activity and life expectancy. Knowledge of anatomy and biomechanics is important for understanding injury patterns, specific diagnosis, and therapy. Here we classify the most frequent elbow injuries such as dislocation, ligamentous instability, and fracture of the radial head, processus coronoideus, olecranon, and distal humerus based on joint anatomy, biomechanics, clinical examination, and imaging. Specific therapies are described.

Monteggia-Verletzungen im Erwachsenenalter

BACKGROUND

Complications, revision surgery, and unsatisfactory functional results after operative management of Monteggia fractures are frequent. Moreover, hardly any studies exist that deal exclusively with the therapeutic concept for adults.

PATIENTS AND METHODS

Between January 1988 and December 2001, 68 patients with Monteggia fractures or equivalent injury were surgically treated. A total of 49 patients could be followed up after 83 months (25-176). Fracture type was assessed according to Bado's classification, functional results according to the Mayo elbow performance score, and the extent of osteoarthritis based on the criteria of Baird and Johnson.

RESULTS

The median age of the follow-up patients was 38 years (18-89, 31 men, 18 women). Corresponding to Bado's classification the following injuries were observed: 18 cases of type 1, 22 of type 2, 5 of type 3, and 4 cases of type 4. After surgical intervention, 14 patients achieved "very good", 21 "good", 9 "satisfactory", and 5 "poor" results. Of the 14 patients with either "satisfactory" or "poor" results, 9 manifested a type 2 injury. Complications requiring revision surgery occurred in 14 patients and complications not requiring revision in another 14. Severe osteoarthritic changes in the humeral or radioulnar joint were observed in 4 cases.

CONCLUSIONS

Monteggia fractures in adults are fraught with complications despite good functional results in the majority of cases. The patient should be made aware early on of the risk of residual functional deficits and the need for further surgical intervention.

A thermostable enzyme as an experimental platform to study properties of less stable homologues

The structural and functional characterization of proteins is frequently hampered by lack of stability or by insufficient assembly of oligomeric proteins in over-expression systems. Using F(1)-ATPase as a case study, we tackled this problem by introducing function-determining domains from a difficult-to-handle variety of an enzyme into a stable homologue.

Fresh meniscal allograft transplantation and autologous ACL/PCL reconstruction in a patient with complex knee trauma following knee dislocation--a case report

Instability of the knee joint, particularly in combination with the loss of one meniscus, regularly leads to the early development of arthritis. This paper describes the case of a 19-year-old male with ruptures of the anterior (ACL) and posterior cruciate ligament (PCL) along with the loss of the medial meniscus due to knee dislocation. Combined, time-delayed reconstruction of both the ACL and PCL and the allogenic fresh meniscal transplantation of the medial meniscus without bone plugs were performed. The control arthroscopy performed 6 months post-transplantation revealed good vitality and integration of the grafts as assessed both macroscopically and histologically. A small portion of the posterior horn had to be refixated, and the anterior horn was atrophic. At 24 months after trauma and 13 months following meniscal transplantation, the patient achieved a Lysholm score of 88 points and clinical examination indicated a stable knee. Fresh meniscal allograft transplantation, in combination with autologous ACL and PCL reconstruction, constitutes--in specialized centers--an alternative treatment option for complex trauma of the knee joint with loss of a meniscus.

Complete inhibition and partial Re-activation of single F1-ATPase molecules by tentoxin: new properties of the re-activated enzyme

During hydrolysis of ATP, the gamma subunit of the rotary motor protein F(1)-ATPase rotates within a ring of alpha(3)beta(3) subunits. Tentoxin is a phyto-pathogenic cyclic tetrapeptide, which influences F(1)-ATPase activity of sensitive species. At low concentrations, tentoxin inhibits ATP hydrolysis of ensembles of F(1) molecules in solution. At higher concentrations, however, ATP hydrolysis recovers. Here we have examined how tentoxin acts on individual molecules of engineered F(1)-ATPase from the thermophilic Bacillus PS3 (Groth, G., Hisabori, T., Lill, H., and Bald, D. (2002) J. Biol. Chem. 277, 20117-20119). We found that inhibition by tentoxin caused a virtually complete stop of rotation, which was partially relieved at higher tentoxin concentrations. Re-activation, however, was not simply a reversal of inhibition; while the torque appears unaffected as compared with the situation without tentoxin, F(1) under re-activating conditions was less susceptible to inhibitory ADP binding but displayed a large number of short pauses, indicating infringed energy conversion.

Die winkelstabile Plattenosteosynthese (LPHP®) proximaler Humerusfrakturen über den kleinen anterolateralen Delta-Splitting-Zugang - Technik und erste Ergebnisse

The Locking-Proximal-Humerus-Plate (LPHP) was slided from proximally to distally through a small anterior-lateral-deltoid-splitting-approach following a closed reduction. Additional tension band wiring for the rotator cuff was fixed at the plate after screw insertion. The prospective study included 35 patients (age median: 63 years, range: 33-92; male: 13, female: 22) from 08/01-05/02. The follow-up period was set to 3 months postoperatively, whereas 29 patients were able to attend. The patient-group with 2-part fractures (n = 8) showed an average Constant score of 77.6 points (+/- 10.7, "good"), the patients with 3-part fractures (n = 16) an average score of 75.1 points (+/- 14.4, "good") and the patients with 4-part fractures (n = 5) an average score of 64.8 points (+/- 10. 4, "moderate"). Specific, approach-related problems were not observed. Almost all fractures revealed bony union during the first 3 months and only one loss of reduction was found. A screw loosening in 2 cases and a break of the plate in 3 cases were seen as implant related problems, and furthermore in 5 cases the screws placed in the humeral head were too long. Only one early re-osteosynthesis with the same plate was necessary due to an initial non-correct reposition. As demonstrated by these good short-term results, this technique seems to be a suitable procedure for displaced humeral head fractures.

[Arthroscopy for anterior joint pathology at the upper ankle joint --pathogenesis, therapy and results]

The conservative treatment of chronic ankle pain and at the so-called "footballer's joint" is of limited success. Arthroscopy is a possibility of operative treatment. 25 arthroscopies were carried out at the upper ankle joint at anterior joint pathology from January 1998 to June 1999. 21 patients could be examined in a median follow-up of 16 months (4-24). The median age was 31 years (17-56; female: 6, male: 15). Synovilitis was found in all cases. In 9 cases exophytes of the tibia, in 10 cases osteochondral lesions and in 7 cases antero-lateral impingement ware seen. The preoperative Score of Mazur of median 63 (21-85) points showed a significant raise (p < 0.05) in follow-up to median 93 (81-100) points. The complete athletic rehabilitation could be restored in 2/3 of the patients. The conservative therapy represents a good method of treatment chronic troubles in the upper ankle joint. Arthroscopy is indicated if no recovery can be attained.

Proximal humeral fractures: how stiff should an implant be? A comparative mechanical study with new implants in human specimens

BACKGROUND

The objective of this study was to determine the in vitro characteristics of the clinically used and newly developed implants for the stabilization of proximal humeral fractures under static and cyclic loading. The goal was to optimize implant stiffness for fracture stabilization even in weak bone stock.

METHODS

In a laboratory study using 35 fresh human humeri, the specimens were randomized into 5 groups, which included the clinically used humerus T-plate (HTP), the cross-screw osteosynthesis (CSO), the unreamed proximal humerus nail with spiral blade (UHN), the recently developed Synclaw Proximal Humerus Nail (Synclaw PHN) and the angle-stable Locking Compression Plate Proximal Humerus (LCP-PH). The implant stiffness was determined for three clinically relevant load cases: axial compression, torsion and varus bending. In addition, a cyclic varus-bending test was performed to determine the implant properties under cyclic loading.

RESULTS

In contrast to a rather elastic and minimally invasive implant(LCP-PH), the conventionally designed ones (Synclaw PHN, CSO, HTP, UHN) showed rather high stiffness values under static loading. In cyclic loading, a strong decrease in stiffness ( p<0.05) was found for the rigid implants HTP and UHN. In comparison with the other implants, only the elastic implant (LCP-PH) showed a significantly lower load reduction in a weak bone stock (17+/-6.2%).

CONCLUSION

The high initial stiffness of rigid implants led to an early loosening and failure of the implant-bone interface under cyclic loading. Implants with low stiffness and elastic characteristics, however, appear to minimize the peak stresses at the bone-implant interface, making them particularly suitable for fracture fixation in osteoporotic bone.

[Tibial plateau fracture--biodegradable bonecement-augmentation]

Between October 1996 and January 1999,29 patients (f:16,m:13,age: 22-86) with fractures of the lateral tibial plateau were operated on arthroscopic,fluoroscopic control or were treated with open reduction and internal fixation. 15 of them were retrospective and 14 prospective analysed. The metaphyseal defect after elevation of the depressed fragment was augmented in 11 cases with autologous spongeous bone grafting,in 9 cases with biodegradable bone cement (Norian SRS). Augmentation was unnecessary in 9 cases. The results according to the Lysholm score and the radiological results were good or excellent. Concerning the kind of augmentation no difference was noted. In the Norian SRS-group the duration of postoperative treatment was shorter than in the other group. The duration of partial weight bearing was shorter too. The results of the present study suggest that an injectable calcium phosphate cement may be a competent material for augmentation in lateral tibial plateau fractures because of the application form and the initial high mechanical stability.

Introduction of a carboxyl group in the loop of the F0 c-subunit affects the H+/ATP coupling ratio of the ATP synthase from Synechocystis 6803

The proton translocation stoichiometry (H+/ATP ratio) was investigated in membrane vesicles from a Synechocystis 6803 mutant in which the serine at position 37 in the hydrophilic loop of the c-subunit from the wild type was replaced by a negatively charged glutamic acid residue (strain plc37). At this position the c-subunit of chloroplasts and the cyanobacterium Synechococcus 6716 already contains glutamic acid. H+/ATP ratios were determined with active ATP synthase in thermodynamic equilibrium between phosphate potential (deltaGp) and the proton gradient (deltamuH+) induced by acid-base transition. The mutant displayed a significantly higher H+/ATP ratio than the control strain (wild type with kanamycin resistance) at pH 8 (4.3 vs. 3.3); the higher ratio also being observed in chloroplasts and Synechococcus 6716. Furthermore, the pH dependence of the H+/ATP of strain plc37 resembles that of Synechococcus 6716. When the pH was increased from 7.6 to 8.4, the H+/ATP of the mutant increased from 4.2 to 4.6 whereas in the control strain the ratio decreased from 3.8 to 2.8. Differences in H+/ATP between the mutant and the control strain were confirmed by measuring the light-induced phosphorylation efficiency (P/2e), which changed as expected, i.e., the P/2e ratio in the mutant was significantly less than that in the wild type. The need for more H+ ions used per ATP in the mutant was also reflected by the significantly lower growth rate of the mutant strain. The results are discussed against the background of the present structural and functional models of proton translocation coupled to catalytic activity of the ATP synthase.

[Age- and gender-related distribution of bone mineral density and mechanical properties of the proximal humerus]

PURPOSE

To evaluate age- and gender-related mechanical properties and bone mineral density (BMD) of the proximal humerus at different levels and regions.

MATERIALS AND METHODS

Mechanical indentation testing, DXA, QCT, pQCT and the radiogrammetry (Cortical Index, CI) were carried out in 70 freshly harvested humeri from 46 human cadavers (23 females, 23-males; median age 70.5 years).

RESULTS

In the female group, a high correlation between age and BMD was found (rho = 0.62 to -0.70, p < 0.01) with statistically significant differences between specimens of patients 69 years or younger, and 70 years or older (p < 0.05). In the group of female specimens of age 70 years or older, BMD values were found to be significantly lower compared to their male counterparts (p < 0.05). Regardless of the specimen's age, the highest BMD and bone strength were found in the proximal aspect and in the medial and dorsal regions of the proximal humerus.

CONCLUSION

These findings provide an insight into the fracture mechanism of the proximal humerus and should be the basis for designing structure-oriented implants with improved implant-bone stability in osteoporotic patients.

[Endoscopically assisted minimally invasive reconstruction of the anterior thoracolumbar spine in prone position]

Irrespective of an anterior open or endoscopic approach, the combined postero-anterior instrumentation of thoracolumbar fractures requires time consuming intraoperative maneuvers changing the patients position from prone to lateral.A standardised anterior endoscopically assisted approach for the segments Th4 to L4 is described, allowing the patient to remain in prone position, using a 4-5cm incision combined with a retractor system. The approach to the anterior spine in prone position is feasible by using a self holding retractor system for the region from Th4 to L4. Time of anaesthesia for the one stage combined procedure can be reduced by about 40 min, when changing the position of the patient is no longer necessary. The minimal incision in combination with the retractor system allows mainly the use of conventional instruments and implants, which provides reasonable lower costs. The advantages of the open and the endoscopical technique are combined. The main advantage of the prone position is the opportunity to access the anterior and posterior spine simultaneously, which is extremely helpful in reduction maneuvers.

[Isolated rupture of the subscapularis tendon in the overhead athlete - the result of chronical overuse?]

The case of a 27-year-old overhead athlete with chronic shoulder pain because of an isolated subscapularis tear without trauma is described. Arthroscopy has proven to be the appropriate method for detailed visualisation of the injury and facilitates the operative planning. Furthermore, arthroscopy closes the problem of a "diagnostic gap". In the presented case, the results at the two year follow-up are excellent. The authors conclude that an operative approach is also justified in non-traumatic isolated ruptures of the subscapularis muscle.

Substitution of a single amino acid switches the tentoxin-resistant thermophilic F1-ATPase into a tentoxin-sensitive enzyme

In contrast to the homologous bacterial and mitochondrial enzymes the chloroplast F(1)-ATPase (CF(1)) is strongly affected by the phytopathogenic inhibitor tentoxin. Based on structural information obtained from crystals of a CF(1)-tentoxin co-complex (Groth, G. (2002) Proc. Natl. Acad. Sci. U. S. A. 99, 3464-3468) we have replaced residues betaSer(66) and alphaArg(132) in the alpha(3)beta(3)gamma subcomplex of the thermophilic F(1)-ATPase from Bacillus PS3 by the corresponding residues of the chloroplast ATPase to confer tentoxin sensitivity to the thermophilic enzyme. The mutation alphaArg(132) --> Pro, proposed to relieve steric constraints on tentoxin binding, did not have any significant effect. However, mutation betaSer(66) --> Ala, predicted to provide a crucial hydrogen bond with the inhibitor, resulted in tentoxin inhibition of ATP hydrolysis comparable with the situation found with the chloroplast enzyme.

Conservative functional treatment of ankle fractures

Thirty-eight patients (mean age 49 years; range 19-91 years; nine of them over 60 years; 28 women, 10 men) suffering from an isolated Weber B fracture with a dislocation of less than 1 mm underwent functional therapy using a pneumatic ankle brace and were included in a prospective study. The clinical outcome was measured according to the Olerud-Molander ankle score. Functional therapy was finished in 34 cases successfully. Twenty-one patients were scored after 17 months on average (range 8-27 months) with the Olerud-Molander ankle score. A very good result was seen in 18 patients, including 12 with 100 points, a complete remission. The remaining 3 patients showed good results (1 had 90, 2 had 85). However, functional treatment failed in 4 cases due to secondary dislocation. These patients underwent surgery without further complications. The control group, 31 operated patients, did not show as good results. Functional therapy of stable Weber-B ankle fractures appears to be superior to surgery. We were able to avoid surgery in 90% of our patients and got better results than with patients undergoing open reduction and internal fixation.

[Conservative or operative treatment of humeral head fractures in the elderly?]

The humeral head fracture in the elderly represents an unresolved problem, which is reflected by the variety of existing therapeutic strategies ranging from conservative treatment to humeral head replacement. The main factors influencing the prognostic outcome are the fracture type, age of the patient and biologic criteria such as osteoporosis, blood supply at the fragments, and the degree of soft tissue trauma. For selection of the optimal treatment, the general condition of the patient, additional injuries and chronic diseases have to be respected as much as the patient's compliance and personal demands. According to experimental and clinical findings, for displaced two- and three-part fractures of the elderly patient minimal osteosynthesis and in the future plate osteosynthesis with angular stability should be preferred. For these fracture types, conservative treatment must be included in the therapeutic spectrum. In contrast, displaced four-part fractures and fracture dislocations are indications for primary humeral head replacement. This is explained by the fact that neither conservative treatment nor surgical reconstruction procedures meet the main goal of primary therapy, aiming for early painless mobilization and for timely discharging the elderly patients in their social environment.

[Perioperative local instillation of ropivacaine for postoperative pain relief after surgery on extremities]

INTRODUCTION

The relief of postoperative pain remains one of the most important goals for adequate surgical patient care.

METHODS

Prospective, randomised, double-blinded study, including 118 patients (67 M;/ 51 F; median age 43 years, min. 18, max. 74). Two groups were formed. In the verum group a wound instillation with ropivacaine was performed, in the control group not. Intensity of pain, demand for analgesics and satisfaction of the patient were evaluated postoperatively. In 10 patients ropivacaine plasma levels were measured.

RESULTS

Significant postoperative pain relief and a decrease in analgesic consumption were found on instillation of ropivacaine. Compared to the control group, patients receiving ropivacaine were significantly more satisfied with the postoperative pain management. Potential toxic plasma levels were not found.

CONCLUSION

By the presented method, the surgeon actively contributes to a significant reduction in postoperative pain and analgesic consumption. Furthermore, the patient's benefit is reflected by higher satisfaction with the pain management. Complications due to toxic plasma levels are not seen.

Arthroscopic-assisted simultaneous reconstruction of the posterior cruciate ligament and the lateral collateral ligament using hamstrings and absorbable screws

Arthroscopic-assisted simultaneous reconstruction of the posterior cruciate ligament (PCL) and the lateral collateral ligament (LCL) using hamstring tendon grafts is described. The femoral tunnel is drilled through an incision over the medial femoral condyle and the tibial tunnel through the same skin incision used for harvesting the tendon graft. PCL reconstruction is performed using a 4-strand hamstring tendon graft and absorbable screw fixation. The tendon of the semitendinosus muscle of the uninvolved knee is used as a lateral loop for LCL reconstruction. After pulling the transplant through the fibular head, femoral fixation of the loop is made with an absorbable screw.

[Crossed screw osteosynthesis of proximal humerus fractures]

Between March 1997 and October 1999 thirty-one patients with displaced proximal humeral fractures were treated with crossed screw osteosynthesis. Insertion of the screws was realized by using a deltoideo-pectoral approach placing the screws anteriorly and posteriorly in a crossed manner from the distal fragment into the humeral head. Additionally, in all two-part-fractures a tension band was applied. In all three-part-fractures, the greater tuberosity was reattached by additional screws. In 21 patients (14 female, 7 male, median age 62 years, 18-86) a clinical and radiological follow-up (median 18 months, 10-29) was obtained. Fractures were classified as two-part-fractures in 10 patients and as three-part-fractures in 11 patients. According to the Constant-Score, "excellent" and "good" results were achieved in 15 patients, "moderate" results were found in 3 patients. However, in 3 patients results were only "poor" (1 two-part-, 2 three-part-fractures). The complication rate was 29% (premature hardware removal due to head perforation in 3 cases; humeral head necrosis necessitating prosthetic replacement in 2 patients; secondary displacement in 1 case). Crossed screw osteosynthesis represents an justified alternative in the surgical treatment of displaced proximal humeral fractures permitting early functional therapy.

[Fracture of the acromion. Diagnosis--treatment strategy--outcome]

The case of an 22-year-old man is presented, who sustained a dislocated fracture of the left acromion process and a not dislocated fracture of the left scapular body with a large subcutaneous décollement as well as a dammage of nervus axillaris occurring during a traffic accident. After resuming diagnostics by means of CT, a tension banding of the ventral part of the acromion and a plate osteosynthesis of the dorsal part was performed. 7 weeks after injury neurolysis of nervus axillaris has been done. 4 months after accident the patient shows a satisfying functional result in the Constant score. Diagnostic, treatment and functional results after operative treatment of dislocated fractures of the acromion are shown and discussed.

The fibrin intermediate, its place in the fibrinogen-fibrin transformation

Our preceding study indicated that, in course of coagulation of human fibrinogen by thrombin, substantial production of the fibrin intermediate (alpha-profibrin) lacking only one fibrinopeptide A (FPA) precedes the formation of alpha-fibrin monomer lacking both FPAs. The plateau concentration of alpha-profibrin (20% of initial fibrinogen) appearing in reactions indicated, however, that the second FPA is released four times faster than the first. The study reported here confirms those findings, and provides new insight into the significance of differing rate constants for the production of alpha-profibrin and its conversion to alpha-fibrin. The intermediate could be isolated in a distinct electrophoretic band by electrophoresing partial thrombin digests at high concentrations. Its identity was verified by digesting it with CNBr and by demonstrating that its N-terminal domain, the NDSK fragment, both lacks an FPA and contains an FPA, unlike the NDSKs of the bands from fibrin which contained no FPA or the fibrinogen band that lacked no FPA. The single step isolation also enabled us to confirm the 15-20% plateau level of alpha-profibrin in course of thrombin reactions, well below the 37% maximum that would be expected if release of the first and second FPA proceeded independently with no difference in rate. The 37% maximum is observed in reactions with atroxin, and it is suggested that the abundant production of alpha-profibrin underlies the therapeutic utility of atroxin as a defibrinating agent. Gel chromatography procedures were optimized for isolation of alpha-profibrin/fibrin mixtures free of fibrinogen, the final step of which involves literal use of agarose gel as a filter to remove fibrin aggregates from the fibrinogen free fractions (aggregates are left behind in gel filtration, rather than their moving ahead in gel chromatography). Unlike human fibrinogen, rabbit fibrinogen does not yield much alpha-profibrin in course of its conversion to fibrin, less than 10% as determined by electrophoresis and comparison with abundant production with atroxin. This low production of alpha-profibrin conformed with conclusions from our early studies on the generalized Shwartzman reaction in rabbits, and we now infer that the low production of alpha-profibrin and rapid conversion to fibrin by rabbit fibrinogen underlies the unparalleled susceptibility of these animals toward fibrinoid formation in the generalized Shwartzman reaction.