[Balancing technique using bone cuts]. / Technik des Balancings durch Knochenschnitte.

BACKGROUND: Kinematic alignment means a surgical technique that focuses on intraarticular balance and laxity and takes into consideration the prearthritic state of the knee joint. AIM: The aim of kinematic alignment is a constitutionally aligned joint space line and balanced tension of the soft tissue covering. By avoiding the proximalization of the joint line and the release of the ligaments, the risk of destabilization of the original physiology of the joint is reduced. METHODS: After resections and recuts of the distal femur, a natural distal femoral joint line in full extension and the posterior line in 90° should be maintained or restored. Therefore, the flexion-extension axis of the femur, around which the knee joint moves, does not change. The principle of KA unequivocally requires the distal femoral cut to be performed before resection of the posterior femoral condyles. RESULTS: The result is a natural knee joint alignment that approximately replicates the anatomy of the femoral and tibial axes. Release of the ligaments is rarely required and all necessary adjustments are usually made using bone recuts.

[Evolution of total knee arthroplasty. From robotics and navigation to patient-specific instruments]. / Entwicklung der Knieendoprothetik. Von der Robotik über die Navigation zu den patientenspezifischen Instrumenten.

In this article the evolution beginning with the robotics of total knee arthroplasty to CT-based and kinematic navigation and patient-specific instruments is described. Thereby it is pointed out that in the early 1990s, CT imaging solely for the planning of a knee endoprosthesis was considered as obsolete radiation exposure and this led to the widespread development of kinematical systems.Also a patient specific planning tool based on CAD built acryl harz blocs existed at the time. There is an ongoing process of implanting total knee arthroplasties in a more exact position. Nowadays the new evolution of soft tissue balancing by using a kinematic alignment has put these efforts into perspective.

[Minimally invasive unicondylar knee replacement with computer navigation]. / Minimal-invasive navigiert implantierte unikondyläre Knieendoprothese.

METHODS: From January 2003 to July 2005 a total of 50 St Georg medial knee monosleds with metal-backed tibial components in stably seated form and Uniglide prostheses (Alphanorm/Corin) with mobile bearing onlays were implanted in minimally invasive operations. Postoperatively the alignment-especially of the tibial components-was investigated, to check whether we had achieved the dorsal slope we had been aiming at, i.e. 5-7 degrees , in the region of these knee replacements. RESULTS: Before surgery there were initial malalignments of up to 10 degrees varus and 3 degrees valgus. All leg axes were restored to between -3 degrees and +3 degrees . The desired dorsal slope of 5-7 degrees for the knee monosleds relative to the tibial component was realized, the average slope being 5.3 degrees . The a-p alignment of the tibial component and of the femoral component was correct. CONCLUSIONS: Use of the navigation system leads to more accurate and reproducible results in terms of tibial dorsal slope, which is extremely important when these monosleds are used. Overcorrection of the leg axis is generally avoided. The use of too-high medial onlays is also reliably avoided by the navigation system's monitoring of the level of the cut.

[Optimization of cup positioning in THA--comparison between conventional mechanical instrumentation and computer-assisted implanted cups by using the orthopilot navigation system]. / Optimierung der Pfannenpositionierung in der Hüftendoprothetik--vergleichende Untersuchung freihandimplantierter und computerassistiert platzierter Hüftpfannen mit dem Orthopilot-Navigations-System.

AIM: The goal of the current study was to determine the accuracy of free-hand and computer-assisted cup replacement. MATERIAL AND METHODS: We analysed the cup positions after 50 conventional instrumented THAs and compared them with the positions of 50 navigated cups. The operations were done between October 2002 and November 2004. To determine the accuracy of the cup position, the author developed a special measurement tool. With the help of the method it was ensured that the radiograph central beam reached the pelvis in a horizontal position. The central beam was focused directly on the head. We calculated the anteversion and the inclination. RESULTS: The variability of the cup position was significantly higher in the free-hand implanted group. The standard deviation for antetorsion in the navigation group was 5.0 and for inclination angles 2.8. In the conventionally implanted group the standard deviation was 7.4 for inclination and 6.9 for antetorsion. In particular, the anteversion cannot be exactly calculated without a navigation tool since the individual position of the patient's pelvis cannot be assessed by the surgeon without aids. Clinical long-term studies for the clarification of a higher stand-time of the computer-navigated cups are still necessary.

[Side effects and complications of injection therapy for degenerative spinal disorders]. / Nebenwirkungen und Komplikationen der Injektionsbehandlung bei degenerativen Erkrankungen der Wirbelsäule.

AIM: The type and frequency of side effects due to treatment of vertebral pain syndromes with local injections were examined. Risks and complications were evaluated and precautions are presented in order to avoid these problems. METHODS: The medical records of 453 patients who had undergone injection therapy in hospital for spinal pain syndromes were investigated retrospectively. RESULTS: Paravertebral injections with cervical and lumbar spinal nerve analgesia, facet joint injections, lumbar epidural-perineural injections, epidural-dorsal and epidural-sacral injections, and injections next to the ileosacral joint were administered, amounting to a total of 7 963 injections. In 25 cases (0.3 %) unfavourable side effects were observed. Epidural-perineural injections led to headache in 10 cases and paravertebral lumbar nerve analgesia in 3 cases. Five times after epidural-perineural injections circulatory dysregulation with vertigo, nausea and decreased blood pressure was observed. One patient fell after an epidural-perineural injection, and one patient developed a sensory block up to the thoracic segment 6. Five patients showed local allergic reactions at the injection site after Mepivacain. All complications could be treated with simple symptomatic measures and had no severe effects. CONCLUSION: Compared to other studies, only few side effects were observed. The injections described above may thus be regarded as low-risk therapy.

[Osteomyelitis after endoprostheses]. / Osteomyelitis nach Endoprothesen.

Today over 170,000 total hip arthroplasties and about 70,000 total knee arthroplasties are performed in Germany. An overall infection rate of 0.5-1.4% is reported in the literature. This means that 800-1700 infections after total hip arthroplasty and 300-850 infections after total knee arthroplasty can occur. The surgical treatment of early or late infections after arthroplasty of the hip or knee needs different intervention. Depending on when the infection develops, a simple Débridement, an allinone exchange arthroplasty, or the explantation of the endoprosthesis with implantation of a spacer followed by the reimplantation of a new prosthesis must be performed. The first hint of postoperative infection is the increase of the C-reactive protein. By correct treatment of the postoperative wound the first sign of an infection can be detected early.

[Computer-assisted navigated cup placement in primary and secondary dysplastic hips]. / Computerassistierte Hüftpfannennavigation bei primär- und sekundär dysplastischen Ausgangssituationen.

AIM: The positioning of an acetabular implant has great influence on the range of motion as well as the charger of dislocation of total hip arthroplasty. Using modern CAS systems the reproduction of the cup position after three-dimensional planning based on computed tomography is possible. We investigated the reliability of the position of the acetabular implant in primary and secondary dysplastic cases. METHOD: Within a prospective randomised study in a total of 100 hip replacements with postoperatively controlled cup position using a computed tomography, we reinvestigated especially the 18 dysplastic and two secondary dysplastic cases. RESULTS: In the dysplastic cases we could realise nearly the same anteversion angles (22.4 degrees to 21.5 degrees) with a bigger standard deviation (+/- 7.68 degrees to +/- 7.29) than in the normal collective. Even the inclination angles (44.5 degrees +/- 5.47 degrees) could be realized nearly the same as in the normal cases (42.3 degrees +/- 4.31 degrees). The depth of the cup implantation could be realised in 15 of 18 cases. CONCLUSION: The CAS system is helpful even in dysplastic cases. The advantage of three-dimensional preoperative CT-based planning is apparent. The surgeon is not able to plan and realise the ideal cup position in some individual.

[Intervertebral disk displacement and trauma]. / Bandscheibenvorfall und Trauma.

It is difficult to find medical evidence of a correlation between a lumbar disk disease and trauma. One should consider whether the individual degeneration of lumbar disks or the trauma lead to the typical complaints. Disk disease in the population are very common. Therefore the relevance of the individual affection before trauma has to be considered. Spinal trauma with its sudden, incidental onset needs to be differentiated from purposeful and conscious movements. An intervertebral disk disease can be classified as accident related only in cases involving adequate trauma, with no previous complains, and a sudden onset of pain.

[A case report: ochronosis in combination with chondrocalcinosis]. / Ein Fallbeispiel: Ochronose in Kombination mit Chondrokalzinose.

We report the case of a 70 year old female patient suffering from Cox- and Gonarthrosis, a massive loss of function of the whole vertebral spine caused by a combination of Ochronosis and Chondrocalcinosis. The patient's anamnesis, the clinical findings and the pathology with the possible clinical manifestations are being described with a review on the existing literature.

A prioritization and analysis strategy for environmental surveillance results.

DOE facilities are required to conduct environmental surveillance to verify that facility operations are operated within the approved risk envelope and have not caused undue risk to the public and the environment. Given a reduced budget, a strategy for analyzing environmental surveillance data was developed to set priorities for sampling needs. The radiological and metal data collected at Sandia National Laboratories, New Mexico, were used to demonstrate the analysis strategy. Sampling locations were prioritized for further investigation and the needs for routine sampling. The process of data management, analysis, prioritization, and presentation has been automated through a custom-designed computer tool. Data collected over years can be analyzed and summarized in a short table format for prioritization and decision making.

Percutaneous lumbar discectomy in the treatment of lumbar discitis.

Lumbar disc infection, either after surgical discectomy or caused by haematogenous spread from other infection sources, is a severe complication. Specific antibiotic treatment has to be started as soon as possible to obtain satisfactory results in conservative treatment or operative fusion. The aim of this study was to analyse 16 cases of lumbar disc infection, treated with percutaneous lumbar discectomy (PLD) to obtain adequate amounts of tissue for histological examination and microbial culture. Between 1990 and 1994, 26 patients with vertebral osteomyelitis were treated. Sixteen patients, with an average age of 41.4 years (range 14-59 years), underwent a diagnostic PLD. Eight of them showed only moderate changes on computed tomograms (CT scans) and magnetic resonance (MR) images in the initial stages of the disease. The other eight showed more or less extensive osteolytic lesions of one or both vertebral bodies adjacent to the involved disc. The histology results showed non-specific discitis in nine patients and tuberculosis in one. In two patients an open biopsy had been performed, which showed non-specific discitis. Microbiological analysis revealed specific infection in 45% of the patients. These patients received a specific antibiotic treatment after antibiogram for an average of 33 days. Only three patients were treated surgically, with evacuation of the disc space and interbody fusion; the whole group received a spondylitis brace. All patients obtained satisfactory clinical results at the last follow-up regarding pain, mobility and spontaneous fusion of the involved disc space. In conclusion, PLD is a very helpful minimally invasive procedure in conservative treatment of lumbar discitis.

Verification of the position of pedicle screws in lumbar spinal fusion.

Medial or lateral pedicle screw penetration with the potential to affect neural structures in a wellknown and frequent problem associated with posterior spinal fusion. We evaluated the placement of pedicle screws (n = 141) in 36 patients following posterior lumbar spinal fusion with Socon or Kluger instrumentation via a lateral transpedicular approach. The examination was based on CT and MR images performed after removal of the instrumentation, on average 1 year after implantation. We found seven pedicle screws with lateral cortical penetration of the pedicle and five screws with medial cortical penetration of the pedicle (8.5% pedicle penetration overall). No severe radicular complications accompanied these pedicle penetrations. The mean insertion angles of the pedicle screws at the L4 level were 22.6 degrees and 23.1 degrees for the left and the right side, respectively. At the L5 level the mean insertion angle was 20.5 degrees on the left side and 21.5 degrees on the right, and at the S1 level the mean angle was 16.2 degrees on the left and 15.2 degrees on the right. The results of this study indicate that the lateral transpedicular approach is a safe procedure for pedicle screw insertion.

External fixation of open femoral shaft fractures.

OBJECTIVE: To determine whether external fixation proves to be a sensible technique for definitive stabilization in open femoral fractures. DESIGN: Retrospective clinical study. MATERIALS AND METHODS: From 1985 to 1989, 18 patients (mean ISS 25.4) with open femoral fractures (type II 11%, type III 89%) were treated by primary and definitive external fixation. After failure of closed reduction procedures, open reduction via debrided soft tissue wounds was employed in 72%. Supplemental internal fixation of large wedge fragments was required in 66%. External fixators were removed after a mean of 166 days. Early deep infections developed in 11%. Additional cast, brace, or traction were not required. MEASUREMENTS AND MAIN RESULTS: After a mean follow-up period of 58 months, 88% of the surviving 17 patients were clinically and radiologically evaluated and 12% were interviewed by telephone. Eleven percent developed late deep infection of the femur concerned. Eighty percent have had full or slightly restricted knee motion. The mean knee flexion amounted to 130 degrees. Relevant shortening of the femur was diagnosed in 7%. Nonunions or relevant malunions were not observed in our series. CONCLUSIONS: These morphologic and functional results compare with those published for alternative stabilization techniques of femoral fractures. For special indications, external fixation is considered to be a sensible technique for primary and definitive treatment of open femoral fractures.

[Comparative study of surgically treated shoulder injuries with or without metal implants]. / Vergleichende Untersuchung operativ versorgter Schultereckgelenksverletzungen mit und ohne metallische Implantate.

In 36 patients with acromioclavicular fracture type III, IV and V following the Rockwood classification, different surgical procedures without using metal implants were compared. Augmentation of both, the coracoclavicular and acromioclavicular ligaments was done by Vicryl-threads (5 mm) in 26 cases (group I). Solitary augmentation of coracoclavicular ligaments were done in 6 cases (group II), of acromioclavicular ligaments in 4 cases (group III). Twenty-four patients underwent follow-up regarding clinical, ultrasonic and radiological results after 30 month in average. Dislocations of more than 10 mm we found once in group I and II, three times in group III. Using the Taft score, regarding clinical, ultrasonic and radiological findings, five patients had an excellent, 15 a good five patients a satisfying result and the remaining patient had a poor reconstruction of the acromioclavicular joint. Comparing these results with previous 75 patients who underwent surgical reconstruction of acromioclavicular joint, using metal implants between 1980 and 1985, the results were nearly equal. Although severe complications like migration or fracture of the implant and the necessity for another surgical intervention for explantation were not given in patients who were treated without using metal implants. Solitary augmentation of acromioclavicular ligament showed insufficient results, therefore this therapy should not be recommended anymore.

Intraarticular autogenous bone grafting in recurrent shoulder dislocations.

In a reexamination, 24 young soldiers who had been operated on using a new method of screwing an autogenous bone graft into the glenoid rim in cases of recurrent dislocation of the shoulder joint were investigated. A major functional problem is the reduced lateral rotation, even by using other procedures for operative treatment like Eden-Hybinette or Putti-Platt. This reduction of shoulder movement results in problems using the affected arm during sporting activities or military duties. There has been an excellent result without any redislocation in a follow through of 6 to 42 months and more than 90% satisfied patients, with only a very low rate of reduction of lateral rotations about 10 degrees using this procedure. The X-rays of all the patients, reinvestigated, showed a complete healing of the bone grafts into the glenoid rim and correct position of AO-screws.