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Biomedical subjects

P Keppler

Publications and source records attributed to P Keppler.

At least 19 recordsLinked to original sources
PubMed2001

[Corrective osteotomies of the distal femur with retrograde intramedullary nail].

Deformities of the distal femur are usually corrected by supracondylar osteotomy. In the "classical" procedure the bone cut is performed with an oscillating saw, and internally fixed using a plate. This technique is hampered first by an invasive approach and second by limited corrective options in case of complex deformities. A supracondylar bone cut by focal dome osteotomy or drill osteoclasis in combination with internal fixation by retrograde intramedullary nailing (RN) might be a promising alternative procedure. 12 patients with multidimensional post-traumatic deformities of the distal femur were prospectively enrolled in a study to investigate this new minimal-invasive technique. In all patients a meticulous analysis of leg geometry was done pre- and postoperatively. Details of operative planning, osteotomy and fixation procedure are given as well as the postoperative treatment. 7 corrective osteotomies were one-step procedures, in 5 patients additional lengthening over the RN was performed using unilateral external fixation. The mean follow-up was 15 (range 7-27) months. All of the osteotomies healed in a normal expected time frame. All patients had important functional benefits. In 11 patients the goal of deformity correction was achieved. In one patient the correction in the frontal plane remained insufficient. 6 months after the completion of femoral lengthening osteomyelitis developed in one patient, probably due to a pin-track infection. The infection subsided after early removal of the RN. No further complications were observed. The presented technique is demanding concerning pre-operative planning and surgical realization but it offers a minimal-invasive and promising approach for the correction of multidimensional femoral deformities.

Adult↗
PubMed2001

Computer assisted treatment of pelvis fractures.

The presented approach is the realization of a minimal invasive treatment of pelvis fractures using the computer aided surgery (CAS). Main problem of tracking of major bone fragments after reposition is solved by implementing of 3D ultrasound to obtain intraoperative bone surfaces. Preoperative and intraoperative data sets are matched. Major fragments are tracked. The real time navigation is possible.

Feasibility Studies↗
PubMed2001

Computer simulation of osteotomy correction.

This paper describes a novel approach to correct osteotomy deformities of long bones using virtual reality and image processing techniques on personal computers. The discussed method allows to simulate osteotomy corrections by implementing a single cut and a rearrangement of the dissected bone parts. It allows the surgeon to directly control the pre-operative situation and the post-operative result of the simulation by comparing bone-length, angles, and torsion of the bone. In addition, he or she obtains the coordinates and angles of the planned cut relative to anatomical landmarks.

Bone Malalignment↗
PubMed2000

The effectiveness of ADCON-T/N, a new anti-adhesion barrier gel, in fresh divisions of the flexor tendons in Zone II.

In a prospective randomized clinical trial, ADCON-T/N was investigated with regard to its effectiveness in fresh traumatic injuries of the flexor tendons in Zone II of the hand. Thirty patients participated in the trial. Following a standardized technique of tendon repair, the total active motion (TAM) and total extension lag (TEL) were determined after 12 weeks and evaluated according to the Buck-Gramcko score. Excellent results were achieved in 15 out of 16 patients in the ADCON-T/N group and 12 out of 14 in the control group. However, no statistically significant difference was found between the mean TAM and TEL in the two groups.

Administration, Topical↗
PubMed1999

[Sonographic imaging of leg geometry].

Posttraumatic malalignments are a frequent sequlae of IM nailing of lower extremity fractures. Conventional US has proven to be inferior to CT determinations of tibial or femural length and torsion. A new 3-D US method is presented that allows for accurate single step determination of lower extremity length and torsion without ionizing radiation. A regular US machine with a 5 Mhz linear probe is combined with an US localizer. Reference markers affixed to the lower extremity eliminate errors associated with patient position or motion. The 3-D US method was compared against CT (Ulm's method) in the measurement of torsion and length of the tibia and femur in 50 adults and 50 children. In both methods, the maximum difference of the intraindividual torsional angles and length measurements was 7 degrees and 7 mm. The maximum standard deviation for reproducibility in length measurement was 1.6 mm and 1.5 degrees for angular torsion. The new 3-D US technique was superior to CT in terms of reliability and reproducibility. Clinical advantages of the 3-D US technique include rapidity, independence from patient motion or positioning and the avoidance of ionizing radiation. Indications for 3-D torsional and length determinations include follow-up evaluation of adult and pediatric tibial and femoral fractures, pediatric limb and gait evaluations, and osteotomy planning.

Adolescent↗
PubMed1999

Evaluation of neoadjuvant therapy response of osteogenic sarcoma using FDG PET.

UNLABELLED: According to the current treatment protocol of the Cooperative Osteosarcoma Study (COSS), monitoring preoperative chemotherapy response and estimating grade of tumor regression in patients with osteosarcoma is mandatory before surgical removal of the tumor, particularly if a limb salvage procedure is intended. In addition, response to neoadjuvant chemotherapy is considered as an important prognostic indicator. The aim of this prospective study was to assess the usefulness of 2-(18F) fluoro-2-deoxy-D-glucose (FDG) PET in the noninvasive evaluation of neoadjuvant chemotherapy response in osteosarcoma. METHODS: In 27 patients with osteosarcoma, we determined tumor-to-background ratios (TBRs) of FDG uptake with PET, before and after neoadjuvant chemotherapy according to COSS 86c or COSS 96 protocols, respectively. We compared changes in glucose metabolism of osteosarcomas with the histologic grade of regression in the resected specimen, according to Salzer-Kuntschik, discriminating responders (grades I-III; n = 17) and nonresponders (grades IV-VI; n = 10). RESULTS: The decrease of FDG uptake in osteosarcomas expressed as a ratio of posttherapeutic and pretherapeutic TBRs showed a close correlation to the amount of tumor necrosis induced by polychemotherapy (P < 0.001; Spearman). With a TBR ratio cutoff level of 0.6, all responders and 8 of 10 nonresponders could be identified by PET. In addition, lung metastases of osteosarcoma were detected with FDG PET in 4 patients. CONCLUSION: FDG PET provides a promising tool for noninvasive evaluation of neoadjuvant chemotherapy response in osteosarcoma. This could imply consequences for the choice of surgical strategy, because a limb salvage procedure cannot be recommended in patients nonresponsive to preoperative chemotherapy unless wide surgical margins can safely be achieved.

Adolescent↗
PubMed1999

[CT determination of leg length and torsion in children and adolescents].

Because of different projections and axis constructions, the length and torsion of the lower extremities are sensitive to the measuring method. To judge pathological deformities in children or adolescents it is necessary to know the reference values. In this study, 78 children and adolescents 2-18 years old were included who had a femoral or tibial shaft fracture. Torsion and length were determined by computed tomography at least 3 months after internal fixation according the Ulm method. Only healthy bones were considered for this study. The mean internal torsion of the femur decreased during the growth period from 34.2 degrees +/- 10.3 degrees (x +/- SD) to 19.3 degrees +/- 9.5 degrees. There was only a weak correlation between the age and torsion of the femur. The mean external torsion of the tibia was 32.3 +/- 10 degrees. The 95th percentiles of the intraindividual torsional differences were 14 degrees (x = 4.1 degrees) of the femur (n = 30) and 12 degrees (x = 4.7 degrees) of the tibia (n = 48). The median femoral and tibial intraindividual length differences were 2 mm. The corresponding 95th percentiles were 10 and 9 mm. The aim of the study was to determine the age-dependent torsion and length and their respective differences with a standardized CT method. The range of the normal values was much greater than published in the literature.

Adolescent↗
PubMed1998

[Analysis of leg geometry--standard techniques and normal values].

The diagnosis of malalignments of the lower extremities includes analysis of the geometry of the whole leg. The first step in the diagnostic process is a standardized physical examination. It provides valuable background information for an effective radiological diagnosis. Even with a thorough standardized physical examination it is not possible to define exactly the deformity or decide on an operative procedure. The diagnosis of axis deviations in the frontal plane can be measured on a conventional plain X-ray of the whole leg. In this view it is very important that the knee joints are in a true a.p. view independent on torsional deformities of the lower legs. Today the gold standard to measure the torsion and length of the lower extremities is the CT scan. However, the multitude of analytical methods for CT measurements described in the literature do not lend themselves readily to comparison; thus, it is difficult to identify a clear method of choice. Not every CT measurement is better than a physical examination. Evidence of reproducibility and accuracy is a prerequisite for useful interpretation of the results. Up to this point in the literature there are only reference values for the Ulm CT Method. One alternative is the MR scan, which avoids radiological risks, but the reproducibility and accuracy of the MRI method are not as good as for the CT method. Another alternative is ultrasound, where recent advances in the measurement of torsion and length of the lower extremities have proven competitive with or superior to the accuracy of MRI. The three-dimensional determination of the torsion and length of the lower extremities by ultrasound has now assumed a leading role in the non-radiological diagnosis of malalignments of the lower extremities in children and adolescents. This method furthermore is increasingly being used in preoperative planning of leg deformities in adults.

Adolescent↗
PubMed1998

[Osteotomy of the proximal femur for correction of post-traumatic changes].

Basically, four post-traumatic conditions of the proximal femur can be improved by corrective osteotomies: recurring luxations and subluxations of the hip joint; necrosis of the femoral head; non-unions; deformities. Dependent on the individual situation, the following procedure can be recommended, including diagnosis of deformities and indication and therapy of corrective osteotomies: analysis of the problem from the viewpoint of history, clinical findings and imaging techniques; indication for corrective osteotomy; graphic planning; operation technique. Particularities of post-traumatic conditions with regard to diagnosis, indication and surgical technique are indicated. Only with perfectly tailored concepts can we respond to the individual situation of an individual patient and reflect the variety and complexity of post-traumatic conditions of the proximal femur.

Bone Lengthening↗
PubMed1998

[Analysis of leg geometry].

Analysis of bony geometry of the lower limb comprises frontal, sagittal and longitudinal alignment, as well as length and torsion, including at first the whole leg and finally the femur and tibia separately. Clinical examination assesses the bony geometry, functional aspects, ligamentous and soft tissue conditions, etc. Frontal and sagittal radiographs indicate axial alignment and angles of the hip, knee and upper ankle joint. Apex and size of deformities are defined simultaneously. CT and ultrasound techniques allow the measurement of length and torsion of the whole leg, as well as of the femur and tibia separately, provided those techniques are standardized with proven reproducibility.

Bone Malalignment↗
PubMed1997

[Correcting torsion after intramedullary nailing osteosynthesis of the lower extremity].

Intraoperative control of torsion is delicate in intramedullary nailing of femur and tibia fractures. Post-traumatic torsional deformities cause clinical problems if the rotational 0-position, according to the neutral-0-method, cannot be attained or exceeded. The necessary precondition for every indication and planning of corrective osteotomies is conscientious analysis of the geometry of the lower extremities by clinical means, radiography and computed tomography. Operative procedures and techniques of corrective osteotomies in case of torsional deformities after intramedullary nailing are presented. Preoperatively, the intraindividual torsional differences in 15 patients with maltorsions of the femur were 33 degrees (-37/+50) and in 7 patients with maltorsions of the tibia 23 degrees (-21/+29). Positive signs indicate external and negative signs of internal maltorsions. Postoperatively, the intraindividual torsional differences were 6 degrees (-3/+14) in the femora and 7 degrees (+3/+12) in the tibiae. Therefore, the physiological torsional tolerance of 15 degrees was respected in all 22 patients. Additionally, limb lengthening was realized in 4 patients with shortening after intramedullary nailing of the femur. In 3 patients a one-step procedures with interposition of allogeneic cancellous bone in the osteotomy gap was performed and in one patient continuous callus distraction by external fixation.

Adult↗
PubMed1997

Length and torsion of the lower limb.

Corrective osteotomies are often planned and performed on the basis of normal anatomical proportions. We have evaluated the length and torsion of the segments of the lower limb in normal individuals, to analyse the differences between left and right sides, and to provide tolerance figures for both length and torsion. We used CT on 355 adult patients and measured length and torsion by the Ulm method. We excluded all patients with evidence of trauma, infection, tumour or any congenital disorder. The mean length of 511 femora was 46.3 +/- 6.4 cm (+/-2SD) and of 513 tibiae 36.9 +/- 5.6 cm; the mean total length of 378 lower limbs was 83.2 +/- 11.4 cm with a tibiofemoral ratio of 1 to 1.26 +/- 0.1. The 99th percentile level for length difference in 178 paired femora was 1.2 cm, in 171 paired tibiae 1.0 cm and in 60 paired lower limbs 1.4 cm. In 505 femora the mean internal torsion was 24.1 +/- 17.4 degrees, and in 504 tibiae the mean external torsion was 34.9 +/- 15.9 degrees. For 352 lower limbs the mean external torsion was 9.8 +/- 11.4 degrees. The mean torsion angle of right and left femora in individuals did not differ significantly, but mean tibial torsion showed a significant difference between right (36.46 degrees of external torsion) and left sides (33.07 degrees of external torsion). For the whole legs torsion on the left was 7.5 +/- 18.2 degrees and 11.8 +/- 18.8 degrees, respectively (p < 0.001). There was a trend to greater internal torsion in femora in association with an increased external torsion in tibiae, but we found no correlation. The 99th percentile value for the difference in 172 paired femora was 13 degrees; in 176 pairs of tibiae it was 14.3 degrees and for 60 paired lower limbs 15.6 degrees. These results will help to plan corrective osteotomies in the lower limbs, and we have re-evaluated the mathematical limits of differences in length and torsion.

Adolescent↗