Imaging of hamate bone fractures in conventional X-rays and high-resolution computed tomography. An in vitro study.

RATIONALE AND OBJECTIVES: To examine the ability to image fractures of the body and hook of the hamate bone in conventional X-rays and high-resolution computed tomography (HR-CT). MATERIALS AND METHODS: In an in vitro experiment using 18 cadaver hands, the hamate bone was fractured at different places. Before and after fracture, conventional X-rays were taken in different planes (anteroposterior, lateral, oblique, and carpal tunnel), and HR-CT was performed with 2-mm layer thickness in the axial, sagittal, and coronal plane. RESULTS: Taking into account all the conventional X-ray projections applied, the in vivo experiment revealed a sensitivity of 72.2%, a specificity of 88.8%, and an accuracy of 80.5%. For the HR-CT, the sensitivity was 100%, the specificity was 94.4%, and the accuracy was 97.2%. CONCLUSIONS: Fractures of the body and hook of the hamate cannot always be detected with certainty in the conventional X-ray image, even if different projectional planes are used. The HR-CT is the imaging procedure of choice for further clarification, and an axial or sagittal plane should be selected.

Morphometric study of muscle in congenital idiopathic club foot.

In congenital idiopathic club foot gross morphological changes cannot be assessed in muscle tissue by conventional histopathological techniques. Since, however, recent studies have indicated the presence of neuromuscular anomalies with preponderance of Type 1 fibres in this condition, we have performed histochemical, morphometric and electron microscopic examinations in muscle biopsies of 23 patients with congenital idiopathic club foot deformity. The age of the patients varied between 6 weeks and 12 years, respectively. Muscle biopsy was taken mainly from the flexor group of the affected leg(s) during the surgical correction of the anomaly. No gross pathological changes could be found by histochemical analysis. Morphometric study, however, disclosed abnormalities in the composition of the fibre types. The most prominent change was the percentual increase in Type 1 and decrease in Type 2 fibres in almost all the cases. Electron microscopically, only minor fine structural changes could be found. Since these changes could be assessed soon after birth just as in the later course, they cannot be regarded as the consequence of the abnormal position of the leg. More probably, Type 1 fibre predominance is related etiologically to the congenital club foot deformity.

[The imaging of hamate fractures in the conventional X-ray and CT: experimental results and clinical experiences]. / Darstellung von Os hamatum-Frakturen im konventionellen Röntgenbild und CT: experimentelle Ergebnisse sowie klinische Erfahrungen.

PURPOSE: Examination of the ability to image fractures of the body and hook of the hamate bone in conventional X-rays and HR-CT. MATERIAL AND METHODS: In an in vitro experiment on 18 cadaver hands, the hamate bone was fractured at different localisations. Before and after fracture, conventional x-rays were taken in different projectional planes: a.-p., lateral, oblique and carpal tunnel view, as well as an HR-CT with 2 mm layer thickness in the axial, sagittal and coronal plane. In addition, 15 clinically verified hamate bone fractures (two body and 13 hook of hamate fractures) were reviewed retrospectively to assess the value of the imaging procedures that led to diagnosis. RESULTS: Taking into account all conventional x-ray projections applied, the in vitro experiment yielded a sensitivity of 72.2%, a specificity of 88.8% and an accuracy of 80.5%. For CT, the sensitivity was 100%, the specificity 94.4% and the accuracy 97.2%. In retrospective clinical evaluation, 60% of the existing fractures were identified in the conventional x-ray images. The remaining fractures were detected by additional procedures like scintigraphy, conventional tomography and CT. CONCLUSION: For the diagnosis of fractures of the body and hook of the hamate HR-CT is the imaging procedure of choice, in which case an axial or sagittal plane should be chosen.

Positioning of total knee arthroplasty with and without navigation support. A prospective, randomised study.

We conducted this prospective randomised and externally evaluated study to investigate whether the use of a navigation system during total knee arthroplasty leads to significantly better results than the hand-guided technique. A total of 240 patients was included in the study. All patients received a condylar knee prosthesis. Two surgeons performed all the operations using the Stryker knee navigation system. Exclusion criteria included the necessity for the primary use of constrained implants. The results revealed a highly significant difference between the two groups in favour of navigation with regard to the mechanical axis, the frontal and sagittal femoral axis and the frontal tibial axis (p < 0.0001). The use of a navigation system was therefore shown to improve the alignment of the implant.

The unstable radiocarpal joint in rheumatoid arthritis.

The inflammation of the wrist occurs very early in Rheumatoid arthritis. In cases of wrist deviation the biomechanics of the hole hand are affected. Carpal collaps will severly influence the range of motion (ROM) of the fingers. Operative techniques of how to maintain hand function are discussed. There are different procedures available - partial arthrodesis, arthrodesis and arthroplasty.

[Changes in the vascular endothelium after electro- and thermocoagulation]. / Veränderungen des Gefässendothels nach Elektro- und Thermokoagulation.

An experimental study was performed in animals to investigate the effect of various coagulation techniques on the vascular system. Using a microsurgical procedure, the femoral vein of fifteen rabbits was exposed bilaterally and coagulated until the lumen was closed. Electro- and thermocoagulation systems were applied. The light microscopic examination showed endothelial alterations in the course of the vessel. Analyses with the scanning electron microscope were therefore also performed. Extensive endothelial damage could be detected regularly with monopolar currents; the results were not uniform with bipolar applications. The most favorable conditions were found when thermal coagulators had been used. Damage to the parallel arteries was not detectable to a significant degree in these cases. The toxic effect of the energy applied can be morphologically divided into three stages. It should be considered whether extensive endothelial damage leads to the formation of microthrombi and thus causes clinical complications.

[Value of various suture materials for defect reconstruction of peripheral nerves]. / Stellenwert verschiedener Nahtmaterialien bei der Defektüberbrückung peripherer Nerven.

A total of 40 surgical procedures were performed for bridging defects of the peronaeus nerve in 20 experimental animals (White Russian rabbits) with absorbable and non-absorbable suture materials. To investigate whether differences in the biological behaviour of suture materials may influence the formation of axons in the coaptation areas positively or negatively, the nerves were examined histologically and electrophysiologically and the regeneration process in the m. tibialis anterior, the reacting organ of the n. peronaeus, was assessed by histomorphometric quantification. Despite minor deviations in absolute values, significance tests and statistical evaluation with Wilcoxon's test revealed no significant differences among the groups. We could show that differences in biological behaviour of absorbable and non-absorbable suture materials are without influence on nerve regeneration in the proximal and distal coaptation areas and therefore without effect on the final results of nerve regeneration in defect areas.

[Thermography as an additional study method in the follow-up of reconstructive operations of the hand]. / Thermographie als ergänzende Kontrolluntersuchungsmethode nach Wiederherstellungsoperationen an der Hand.

The hand is very accessible to thermography. Disturbed circulation, vascular disease, tissue damage, or other causes of change in thermoproduction lead to deviation from a normal temperature chart. We found a high correlation between thermographic readings and prognosis after replantation. Thermography is, therefore, a method of examination that can be recommended.

[Effect of ACTH on long-term outcome of muscle regeneration after nerve injuries]. / Der Einfluss von ACTH auf das Langzeitergebnis von Muskelregeneraten nach Nervenverletzungen.

An experimental investigation was performed to examine the influence of ACTH on the long-term results of muscle regeneration after nerve repair. Twenty albino-rabbits ("White Russians") served as the animal model. The epi-perineural neurorrhaphy of the fibular nerve was carried out under microscopic control with 11x0 sutures. A computer-supported light-microscopic analysis of representative muscle-fiber diameters was performed for detection of nerve regeneration on the effector muscle of the peroneal nerve, the anterior tibial muscle, after 3, 4, 5 1/2, 7, and 8 months. In addition, the nerves were examined by light microscopy using not only standard techniques but also surgical immunohistological staining techniques (APAAP). The acceleration of nerve regeneration already described in the literature was confirmed by our investigations. However, the results observed after eight months were similar, regardless of the ACTH dosage applied. Muscle regeneration was not influenced by the injection of ACTH. It therefore does not appear justifiable to clinically apply ACTH for improvement of nerve and muscle regeneration.

[Pathologic humeral fractures]. / Pathologische Humerusfrakturen.

The various diseases are described which cause pathological fractures of humerus. Dependent on the prognosis and localization of the disease a survey on the surgical methods is presented ranging from curettage to exarticulation. The noninvasive treatment is left to osteogenesis imperfecta tarda.

[Simultaneous bilateral total knee arthroplasty in patients with rheumatoid arthritis]. / Einzeitiger bilateraler Kniegelenkersatz bei Patienten mit Rheumatoider Arthritis.

AIM: In the event of destruction of both knee joints, is bilateral total arthroplasty a reliable operation that the patient can reasonably be expected to undergo? METHOD: In 140 patients [35 men, 105 women, average age 48.6 (range 24-78) years], a bilateral sequential TEP implantation was performed under one anaesthesia session, due to verified destruction of both knee joints (Larsen stage III-IV). All patients were treated with a cemented surface replacement prosthesis with resurfacing of the patella (Duracon Total Knee System, Stryker/Howmedica). Functional assessment was done with the aid of the Lysholm score preoperatively as well as 6, 12 and 18 months postoperatively. RESULTS: The operation was conducted under one anaesthesia session in all patients. The average Lysholm scores improved from 26 (19-45) preoperatively, to 72 (49-81) 6 months postoperatively, 76 (48-85) 12 months postoperatively and 77 (49-87) 18 months postoperatively, whereby no significant difference between sides was observed. 96% of the patients said that they would undergo the operation again. The following complications occurred: 6 prosthesis infections (2.1%), 2 aseptic loosenings (0.7%), 8 superficial wound healing disorders (2.9%) and 2 deep vein thromboses (0.7%). CONCLUSION: Sequential bilateral total knee arthroplasty under one anaesthesia session in patients with rheumatoid arthritis facilitates a much quicker rehabilitation, while the overall perioperative risk is not increased.

[The unstable radiocarpal joint in rheumatoid arthritis]. / Das instabile Radiokarpalgelenk bei der rheumatoiden Arthritis.

The inflammation of the wrist occurs very early in Rheumatoid arthritis. In cases of wrist deviation the biomechanics of the hole hand are affected. Carpal collapse will severely influence the range of motion (ROM) of the fingers. Operative techniques of how to maintain hand function are discussed. There are different procedures available - partial arthrodesis, arthrodesis and arthroplasty.

[Multiple surgical possibilities for the correction of acetabulum failure in rheumatoid arthritis]. / Die Mehrfachwechseloperation der Hüftpfanne bei der rheumatoiden Arthritis.

Pronounced osteoporosis of and surrounding the acetabulum commonly leads to early loosening of endoprosthetic hip replacements following implantation. Large osseous defects in the subimplant bed are the result and the reason why multiple revisions of loosened acetabular cups have to be performed so often in rheumatic surgery. The defects extend from the cranial to the central; ventral and dorsal anchorage losses may occur in addition to this. The anchorage of a new implant must be adapted to the individual circumstances. The new implant must be selected in accordance with point of surgical access, the patient's general status and osseous regenerationability. In the optimum case, osseous buildup of lost anatomical structures is the preferred method. If this is not possible, special implants, mostly custom-made prostheses, have to be incorporated. However, the survival time of the implants is much shorter than in patients with degenerative diseases.

[Nerve prosthesis. Current status]. / Nervenprothetik. Aktueller Stand.

To date, every attempt to bridge neural defects with nerve prostheses has failed. Silicone tubes,polyglactides, caprolactones and other compounds containing polyglactin have not solved the basic problems of nerve regeneration. The profound rejection responses to foreign matter cause destruction of the ultrastructural units that are imperative for the regeneration of neurites. Positive results obtained with animal experiments have not withstood clinical testing since inferior regenerative performance can occur despite obstructed regenerative pathways.

[Recent aspects of the biocompatibility of carbon fibers. A histologic and electron microscopy analysis]. / Neuere Aspekte zur Biokompatibilität von Kohlefasern. Eine histologische und elektronenmikroskopische Analyse.

Twenty out of 36 patients who had been treated with a carbon fiber syndesmoplasty were followed up 12-19 months after surgery. Reoperation was performed on 11 patients, in 3 cases for removal of the material and in 8 because of persistent pain, although the syndesmoplasties were stable in the majority of cases. Histologic and electron-microscopic study of the explanted ligaments revealed a considerable foreign-body reaction to the carbon fibers and insufficient metaplasia of the allogenic material to connective tissue.

[Results of early rehabilitation using various knee prosthesis models]. / Ergebnisse der Frührehabilitation bei Verwendung unterschiedlicher Knieendoprothesen-Modelle.

The present contribution deals with the early rehabilitation outcomes achieved using total knee arthroplasties with major differences in design. Hinged and unhinged total knee replacements are compared for a total of 100 patients included in the prospective study (48 hinged prostheses, and 52 unhinged ones). Evaluation of the functional and subjective parameters included shows that major improvements in total scores had been achieved in both groups already after 5 weeks, even more pronounced after 10 weeks. With a number of differences found for the various criteria assessed, it in particular is the fact of early stability of the joint in using the hinged prostheses that entails speedy progress and a good rehabilitation outcome. Due consideration of the different early outcomes for the various parameters, hence, is imperative in pre-operative decision-making.

[Value of navigation and robot-guided surgery in total knee arthroplasty]. / Stellenwert der Navigation und Roboterchirurgie bei Knie-Totalendoprothesen.

Up to now robotics play a minor role in orthopedic surgery because the financing and daily costs of these devices overburden the budgets of normal hospitals. The technical demands are time consuming and pose an additional cost factor. The trauma to the patients in the opinion of some authors is considerable. Nevertheless, robotics play an important role in the further development of orthopedic surgery because improvements in technology will lead to a better operative outcome for the patients. Navigation devices have been developed in the last few years in different centers. From the medical point of view, it is important that navigation systems support surgeons in the analysis of all questions concerning alignment. This pertains not only to rotation analyses of the femur and tibia components but also to analyses of the cinematic gap in flexion and extension. The handling of soft tissues has an important influence on the postoperative function of the knee. It is also a medical issue that the navigation systems should be open, i.e., that different designs of implants could be implanted with one navigation device. There are some systems which offer this quality. Improvements in technology are necessary especially in rotation analyses of the lower limb.

[Loss of innervation of the anterior cruciate ligament in idiopathic gonarthrosis]. / Innervationsstörungen des vorderen Kreuzbandes bei der idiopathischen Gonarthrose.

This study quantifies the neurological structures of the ACL from proximal to distal in the zones A, B and C. 37 knee cadavers of healthy patients were analyzed to determinate the innervation for each age decade. This investigation was undertaken with high specific immuno-histologic sections (APAAP method). Neurofilaments and Schwann cells were isolated identified. In a second group consisting of 15 patients with idiopathic arthritis the ACLs were analyzed. This showed a significant loss of innervation, often, there was a complete deficit. In conclusion, this study revealed that idiopathic arthritis of the knee is associated with a significant deficit of the innervation of the ACL. If this is the reason for the arthritis or a secondary phenomenon is still unknown.

Wrist arthroplasty with a new generation of prostheses in patients with rheumatoid arthritis.

The function of the wrist is frequently considerably impaired by early destruction in patients with rheumatoid arthritis. The aim of endoprosthetic arthroplasty is to restore functional use and provide freedom from pain. In our study a newly developed, uncemented wrist prosthesis was implanted in 30 patients (24 women and 6 men) with advanced destruction of the wrist. This wrist prosthesis is a hydroxyapatite-coated cobalt-chrome prosthesis with a titanium coating of the articular surfaces. The radial component has an articular surface inclination of 10 degrees toward the ulna, and the carpal component, which is anchored with its tip in the distal carpal bones and third metacarpal bone, has a double articular surface with a radial inclination of 10 degrees. At the 18-month follow-up visit, the following parameters were examined: x-ray, grip strength, range of motion, and the patient's subjective satisfaction. Good improvement of function was found in 92% of the patients; 87% were free of pain. Eighty-eight percent of the patients rated the outcome of surgery as good. If the indication is accurately diagnosed, this wrist prosthesis can markedly improve function, which in turn leads to high patient acceptance. Various salvage procedures remain open because of the minimal loss of bone stock and the uncemented implantation of the prosthesis.