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C Bertsch

Publications and source records attributed to C Bertsch.

11 recordsLinked to original sources
PubMed2006

Regression and correlation analysis of preoperative versus intraoperative assessment of axes during navigated total knee arthroplasty.

OBJECTIVE: Modern computer assisted surgery (CAS) systems allow accurate positioning of the implants in navigated Total Knee Arthroplasty (TKA). However, when an operation is performed with a navigation system, it is important to know if the anatomical situation of the knee is reflected equally in both the preoperative image (e.g., CT) and the intraoperative navigation setup. In this study, we compared the preoperative anatomical situation to the virtual intraoperative situation of the navigation setup. MATERIAL AND METHODS: We analyzed 24 navigated operations. Intraoperatively, the condylar twist angle (CTA) was documented with the navigation system by measuring the angle between the transepicondylar axis (TEA) and posterior condyle axis (PCA). This data was compared with the preoperative data from the CT scan. RESULTS: Statistical analysis revealed that there was no correlation between the pre- and intraoperative data (r = 0.095). CONCLUSIONS: Statistically, there is no possibility of collecting the same angles and axes when using the two different methods (CT and navigation) on the same knee. It is not possible to copy the preoperative anatomical situation exactly with the virtual intraoperative data. Reasons for this include systematic errors, as well as inter- and intraobserver errors in both methods.

Arthroplasty, Replacement, Knee↗
PubMed2004

Reconstruction of the lateral ligaments: do the anatomical procedures restore physiologic ankle kinematics?

BACKGROUND: If conservative therapy fails, the standard treatment for chronic ankle instability is surgical reconstruction of the lateral ligaments. For the last seventy years, the tenodesis principles have been used for reconstruction. Recently however, surgical reconstructions--respecting the intact joint anatomy--have been developed, thus called "anatomical reconstruction principles". METHODS: This study focused on the investigation of the range of motion of the ankle and the subtalar joint following anatomical reconstruction surgery. Three different types of anatomical reconstruction procedures were compared: Direct ligament repair, tendon graft and carbon-fiber implant. RESULTS: All procedures restored the original range of motion of the subtalar joint, except for the plantarflexed/dorsiflexed positions. As for the talocrural joint, the tendon graft and the carbon fiber implant left a small laxity for movements of inversion/eversion and internal/external rotation. The direct repair procedure achieved a more accurate result and restored the physiologic kinematics almost completely. During each procedure the insertion points and the direction of the original ligaments were maintained. However, the different results for the procedure of direct ligament repair compared to the other two anatomical reconstruction procedures showed that this condition alone is not sufficient to perfectly restore the kinematics of the talocrural and subtalar joints. It is important to note that none of the procedures caused a restriction of the range of motion. CONCLUSIONS: The maintenance of the range of hindfoot motion decreases the risk of osteoarthritis as well as chronic pain or problems for the patient to walk on uneven surface. Therefore, we believe that standard therapy for chronic instability of the ankle should include direct surgical reconstruction of the ligaments. If this direct procedure cannot be performed because of poor quality of the ligaments an alternative anatomical reconstruction procedure should be considered.

Aged↗
PubMed2003

[CT analysis of leg alignment after conventional vs. navigated knee prosthesis implantation. Initial results of a controlled, prospective and randomized study].

INTRODUCTION: Correct alignment of the leg is one of the significant factors for the outcome after TKA. Previous studies have shown that the use of a navigation system can improve the alignment. However, for the positioning of the femoral component no validated data are available. This article presents the first results of a controlled, prospective and randomised trial comparing navigation versus free-hand implantation in TKA with special reference to the rotation of the femoral component. METHODS: Since January 2003, all patients with primary arthrosis of the knee admitted to our hospital for TKA have been followed prospectively. For this first analysis, data were collected over a period of 5 months. Apart from the usual clinical evaluations, all patients had CT of the leg prior to the operation and 1 week postoperatively. Measurement of axis and rotation was performed by staff members of the X-ray department who had no knowledge of the operation technique (navigation vs. free-hand). RESULTS: Twenty five sets of CT scans have been analysed, from 12 navigated operations and 13 freehand procedures. All 12 of the navigated knees were within the interval of +/-3 degrees varus/valgus deviation, but only 8 of the 13 non-navigated knees met this criteria. The analysis of the rotation position of the femoral component revealed no difference between the two groups. CONCLUSION: By using an intraoperative navigation system, the accuracy of the alignment in TKA can be improved. Long-term studies will have to be carried out to verify whether this will lead to a lasting benefit for the patient. Concerning the rotation position of the femoral implant, no conclusion can be made regarding the recommended rotation position at this point of the study.

Adult↗
PubMed2002

Revision hip arthroplasty in a patient with a hip rotationplasty (type B III b).

We report for the first time a patient who underwent a revision hip arthroplasty after a hip rotationplasty (Winkelmann type B III b) because of a chondrosarcoma in 1988. The clinical symptoms and radiographic findings (X-ray, bone scintigraphy, arthrography) of the aseptic loosening of the acetabular component are presented in detail. Furthermore, we present the functional results after hip revision.

Adult↗
PubMed2002

Properties of a chimeric simian-human immunodeficiency virus expressing an hybrid HIV-1 Nef/SIVmac Nef protein.

The nef genes of human and simian immunodeficiency viruses code for a membrane associated protein critical for AIDS development. SIVmac Nef presents C-terminal a 27 amino acid extension absent of HIV-1 Nef. To estimate the influence of this C-terminal domain on virus properties, we constructed viruses derived from SIVmac239 by replacing SIV nef with HIV-1 Lai nef gene (SHIV NefLai4) or with a sequence encoding a Nef fusion protein: HIV-1 Lai Nef/SIV Nef-Cterm (SHIV-Cterm). The recombinant viruses replicated efficiently in vitro in CEMx174 cells and in activated macaque PBMCs. The addition of SIV Nef C-terminal domain to HIV-1 Nef in SHIVNefLai4 did not change the in vitro properties of the chimeric virus, both viruses being more infectious than a nef deleted virus. Although the half-life of Nef fusion protein was augmented, SHIV-Cterm remained slightly less infectious than SIVmac239.

Amino Acid Sequence↗
PubMed2001

[Intra-articular and plantar pressure distribution of the ankle joint complex in relation to foot position].

Ankle injuries are often followed by degenerative changes in the hindfoot joints. Knowledge about the pressure distribution of the intact ankle joint may help to understand the mechanisms leading to cartilage damage. Therefore, we determined the intraarticular and plantar pressure distribution of the ankle joint complex and the Chopart joints with varying foot positions. 12 human lower leg specimens were axially loaded in a foot-loading simulator with full body weight (600 N). A capacitive pressure distribution platform was used to determine plantar pressure patterns. The intraarticular loading situation was measured with Fuji Prescale film. 3 different foot positions (neutral, 10 degrees dorsiflexion, 10 degrees plantarflexion) were investigated. Dorsiflexion led to an increase of the intraarticular contact area, force and mean pressure in the hindfoot. Plantarflexion instead increased loading in the Chopart joints. In the plantar pressure distribution force and peak pressure under the hindfoot increased with dorsiflexion. With plantarflexion area, force and peak pressure under mid- and forefoot increased. With our study we could demonstrate that the loading situation of the ankle joint complex is significantly influenced by the foot position. These findings may help to understand the development and localisation of arthritic changes due to posttraumatic changes of the joint loading characteristics.

Ankle Injuries↗
PubMed1997

NOVEL Award 1996: 2nd prize Tenodeses do not fully restore ankle joint loading characteristics: a biomechanical in vitro investigation in the hind foot.

OBJECTIVE: In order to understand the biomechanical consequences of ligament injuries and surgical reconstruction procedures, their effects on intra-articular loading in the ankle joint complex and Chopart joint line and on the plantar pressure patterns were investigated in vitro. METHODS: Twelve fresh-frozen lower leg specimens were freed of soft tissue down to the malleoli and prepared for accessing the talocrural, subtalar, talonavicular and calcaneocuboid joints. The specimens were fixed in a loading simulator and axially loaded with 600 N in six experimental conditions: intact; after cutting the anterior talofibular ligament; after additionally cutting the calcaneofibular ligament; after performing three common types of tenodeses, the Evans, Watson-Jones and Chrisman-Snook procedures. The intra-articular loading characteristics were determined with pressure sensitive film. Plantar loading patterns were measured with a capacitive EMED pressure distribution platform. RESULTS: Average intra-articular pressures were increased and were related either to decreased contact areas or to increased contact forces found in all joints after ligament resections and tenodeses. Plantar loading was increased under the medial aspect of the foot and decreased under the midfoot region. CONCLUSIONS: The results indicate that ankle ligament injuries, as well as surgical reconstructions by tenodeses, affect joint loading characteristics and may exacerbate joint degeneration. RELEVANCE: Excessive laxity of the ankle joint is considered a pre-arthrotic condition and is treated with various surgical procedures. Some of these procedures that utilize the tendon of the peroneus brevis have been shown to change joint kinematics. The aim was to evaluate joint loading characteristics and the potential danger of developing arthritis as a consequence of various tenodeses techniques. For this purpose, in vitro investigations are needed to directly determine intra-articular pressure measurements.

Journal Article↗
PubMed1996

[Foot stress simulator for biomechanical in vitro studies of lower leg segments].

In this paper we describe a foot-loading simulator that permits in vitro studies on human lower leg and foot specimens. The specimens are fixed in a jig and loaded axially with the aid of a pneumatic cylinder. The resulting transfer of forces through the ankle joint complex and Chopart's articulation (line) can be demonstrated on a pressure-sensitive film. Plantar pressure measurements obtained in patients or normal subjects can be used to ensure the comparability of in vivo and in vitro measurements. The supporting platform can be tilted in such a manner as to provide a range of foot positions up to 20 degrees in plantar- or dorsiflexion, eversion or inversion. The system is used for investigating the effects on the intra-articular pressures and plantar pressure patterns of physiological muscle activity and pathological conditions following fracture of the calcaneum or damage to the lateral ligament. By way of an example, the effects of muscle forces on plantar pressure distribution are presented.

Ankle Joint↗
PubMedDate not supplied

CREST syndrome: a variant of systemic sclerosis.

A variant of systemic sclerosis (scleroderma), CREST syndrome affects a relatively small number of patients. CREST (also called limited cutaneous scleroderma) has a more favorable prognosis than the diffuse form of scleroderma. However, as with most of the connective tissue diseases, the daily issues faced by patients are frequently difficult to manage and require diligent support from the health care team. This article summarizes the clinical manifestations and potential management plan to help the patient cope with this little-understood syndrome. The nursing care model follows a problem-oriented approach for nursing management.

Adaptation, Psychological↗