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T Hüfner

Publications and source records attributed to T Hüfner.

At least 37 records · Page 2Linked to original sources
PubMed2002

Computer-assisted fracture reduction of pelvic ring fractures: an in vitro study.

A newly developed software module for computer-assisted surgery based on a commercially available navigation system allows simultaneous, independent registration of two fragments and real-time navigation of both fragments while reduction occurs. To evaluate the accuracy three fracture models were used: geometric foam blocks, a pelvic ring injury with disruption of the symphysis and the sacroiliac joint, and a pelvic ring fracture with symphysis disruption and a transforaminal sacral fracture. One examiner did visual and navigated reduction and in all experiments the end point was defined as anatomic reduction. Residual displacement was measured with a magnetic motion tracking device. The results revealed a significantly increased residual displacement with navigated reduction compared with visual control. The differences were low, averaging 1 mm for residual translation and 0.7 degrees for the residual rotation, respectively. Residual displacement was small in both set-ups and may not be clinically relevant. Additional development of the software prototype with integration of surface registration may lead to improved handling and facilitated multifragment tracking. Use in the clinical setting should be possible within a short time.

Biomechanical Phenomena↗
PubMed2001

Computer-assisted fracture reduction: novel method for analysis of accuracy.

Anatomic reduction of displaced fractures is limited by the chosen surgical approach and intraoperative visualization. Preoperative Computed Tomography (CT) enhances the analysis of the fracture pattern and provides accurate spatial relationships. Computer Assisted Surgery (CAS) was introduced to increase the accuracy of specific surgical procedures. CAS systems can be used for implant placement or osteotomies in intact bone or reduced situations prior to obtaining the CT data, as differentiation into different datasets related to specific fragments is not yet possible. We present a model that allows "virtual" controlled reduction, providing computer assistance during the fracture reduction. Prior to clinical application, the accuracy of the process of virtual reduction must be proven in an experimental setting. An in vitro fracture model with two body fragments and a motion tracking system for three-dimensional (3D) control (accuracy 0.1 mm and 0.1 degrees ) was used. Two methods were employed: direct visualization and reduction by the examiner, and "virtual" reduction, performed solely with the use of a computer image, in which the examiner lacks any direct visualization of the fragments. The results of this very simplified "fracture" model indicate that the overall difference between direct and virtual controlled reduction was very small. A significant difference of 0.3 mm (0-1.8 mm) was seen for the residual displacement represented by the Euclidean distance (p < 0.01), whereas the difference in the residual angulation was not significant (p > 0.05). The methods tested revealed that virtual controlled reduction is nearly as accurate as direct visualization. Reduction control utilizing a motion tracker system reveals accurate 3D information in this simplified reduction setup, and is now used as a standard setup for analyzing realistic fracture models.

Fracture Fixation↗
PubMed2001

[Computer-assisted surgery: developments and prospects in 2001. Results of a workshop at Schloss Reisenburg, 23-24 November 2000].

The progress in computer assisted surgery (CAS) is influenced by new technologies in imaging as well as by the input of the users. At present, CAS procedures are established in dorsal spine instrumentation, prosthetics and long bone surgery. Present status and future of CAS was a topic of an expert meeting at the Reisensburg castle. Imaging will speed up in the future using multi-detector techniques. C-arm navigation will gain more information using the 3D technology intraoperatively. CT based navigation procedures are standard in spine and will be established in pelvic surgery. CAS in robotics at the moment means the use of robot-assistance. A new concept is the modality-based navigated surgery, which can be used at various skeletal locations. Visualization of patient data will improve using 3D semi-transparencies with real time update. In the future it will be mandatory to find algorithms to fuse the different possibilities and techniques. A new concept of surgical training is necessary to teach CAS procedures. Therefore discussion must go on to improve these systems.

Arthroplasty, Replacement, Knee↗
PubMed2001

[Computer assisted surgery, 2001 development and prospects. Results of a congress at Reisensburg Castle, 23-24 November 2000]].

The progress in computer assisted surgery (CAS) is influenced by new technologies in imaging as well as by the input of the users. At present, CAS procedures are established in dorsal spine instrumentation, prosthetics and long bone surgery. Present status and future of CAS was a topic of an expert meeting at the Reisensburg castle. Imaging will speed up in the future using multi-detector techniques. C-arm navigation will gain more information using the 3D technology intraoperatively. CT based navigation procedures are standard in spine and will be established in pelvic surgery. CAS in robotics at the moment means the use of robot-assistance. A new concept is the modality-based navigated surgery, which can be used at various skeletal locations. Visualization of patient data will improve using 3D semi-transparencies with real time update. In the future it will be mandatory to find algorithms to fuse the different possibilities and techniques. A new concept of surgical training is necessary to teach CAS procedures. Therefore discussion must go on to improve these systems.

Forecasting↗
PubMed2000

[3-dimensional movement analysis after internal fixation of pelvic ring fractures. A computer simulation].

Several studies exist describing the biomechanical behavior of several external or internal fixation techniques of the posterior and anterior pelvic ring. Recently, the traditional models using isolated anatomical sections or fixed pelvic ring specimens for evaluation of linear or two-dimensional data have been replaced by three-dimensional measurement systems and simulations of muscle forces. These studies have contributed important information to the understanding of the biomechanics of the intact and injured pelvic ring, however, a consequent movement analysis is still missing. In the present study, 3-D data acquired during several series of testing implants for stabilization of the posterior pelvic ring (sacrum: sacral bars, sacral plates, transiliosacral lag screws; Sl joint: anterior plates, transiliosacral lag screws), using a complete pelvic ring model with single leg stance and static abductor muscle simulation, were converted into a commercially available 3-D animation package. By use of simple graphical representation of anatomical elements of the posterior pelvic ring, reproducible and reliable movement patterns for different types of stabilization could be identified, which demonstrated potential "weakness" of the fixation before failure occurred. These movements were analyzed by "replay functions" and were comparable to observations during the original experiment. The following movements were observed. Sacral fracture, transforaminal: (1) rotation of the transiliosacral lag screws around its axis, even with a second screw into S1; (2) Sacral bars: shearing with compression of the cranial-posterior fracture zone; (3) Sacral plates: minimal translation in the proximal fracture zone and distraction in the distal fracture line, effectively compensated by an additional plate at the S3 level. Sl joint disruption: (1) anterior plating (two plates), minimal translation in the plane of the Sl joint; (2) transiliosacral lag screws, rotational movement around the axis of the screws with only minimal movement at the S1 level. The provided information confirmed the observations and allowed a more detailed and comfortable examination of movement patterns. A better understanding of potential "failure zones" might be useful to optimize the dimensions, design, and the positioning of implants for the pelvic girdle. For further studies, more complex computer models including finite element technology might be useful to add accessory information and could result in a decreased need of living specimen testing.

Biomechanical Phenomena↗
PubMed2000

[Post-traumatic osteolysis of the distal clavicle. A case report and review of the literature]].

The post-traumatic osteolysis of the distal clavicle is very infrequent and the etiology and pathology is poorly understood. It is important to consider this possibility for differential diagnosis when continued pain in the acromio-clavicular joint (AC joint) follows blunt shoulder trauma. The course of the disease may result in a 3 cm loss of length of the distal clavicle. Months and years may pass until osteolysis becomes manifest, but the earliest radiological findings are present 4 weeks after trauma. The disease is self-limiting and usually does not leave residues. We report a case of a 35-year-old man with a post-traumatic osteolysis of the distal clavicle after blunt shoulder trauma. The diagnosis was determined several months after pain persisted in his shoulder. Using this case we discuss the possible pathogenic mechanism, differential diagnosis and treatment options for the post-traumatic osteolysis of the distal clavicle.

Adult↗
PubMed2000

[Achilles tendon rupture].

The treatment of acute of Achilles tendon rupture experienced a dynamic development in the last ten years. Decisive for this development was the application of MRI and above all the ultrasonography in the diagnostics of the pathological changes and injuries of tendons. The question of rupture morphology as well as different courses of healing could be now evaluated objectively. These advances led consequently to new modalities in treatment concepts and rehabilitation protocols. The decisive input for improvements of the outcome results and particularly the shortening of the rehabilitation period came with introduction of the early functional treatment in contrast to immobilizing plaster treatment. In a prospective randomized study (1987-1989) at the Trauma Dept. of the Hannover Medical School could show no statistical differences comparing functional non-operative with functional operative therapy with a special therapy boot (Variostabil/Adidas). The crucial criteria for therapy selection results from the sonographically measured position of the tendon stumps in plantar flexion (20 degrees). With complete adaptation of the tendons' ends surgical treatment does not achieve better results than non-operative functional treatment in term of tendon healing and functional outcome. Regarding the current therapeutic standards each method has is advantages and disadvantages. Both, the operative and non-operative functional treatment enable a stable tendon healing with a low risk of re-rupture (1-2%). Meanwhile there is consensus for early functional after-treatment of the operated Achilles' tendons. There seems to be a trend towards non-operative functional treatment in cases of adequate sonographical findings, or to minimal invasive surgical techniques.

Achilles Tendon↗
PubMed1999

[Subtalar fusion after conservative or surgical treatment of calcaneus fracture. A comparison of long-term results].

In a long-term follow-up we evaluated 40 patients out of 55 (73%) with a subtalar fusion. The operations took place from 5/84 to 5/91. In all cases the indication for the fusion was a post-traumatic arthritis after an intra-articular os calcis fracture. The evaluation of the overall results was carried out with three different scoring systems: a. The Hannover Scoring System. b. The Outcome-questionnaire, rating patient's complaints and the functional status based on the severity-symptom scale and functional status described for Carpaltunnel-syndrome by Levine et al. c. The clinical rating system (CRS) described by Kitaoka et al. The statistical evaluation was performed by analysis of variance (ANOVA). Level of significance was based on P = 0.05 and calculation of Pearson's correlation coefficient. The Os calcis fracture was the cause for the subtalar arthritis in all 40 patients (33 males and 7 females). The primary treatment of the calcaneal fracture was conservative (cons.) using a plaster in 23 patients (57.5%), while 17 patients (42.5%) underwent open reduction and plate fixation (op.). The interval between trauma and subtalar fusion averaged 3.5 years (3 months to 20 years). The interval between subtalar fusion and follow-up averaged 5.2 years (4-14 years). The mean age at the time of reexamination was 47 years (26-61 years). In the present study, complete pain relief could be achieved in 21 (52.5%; 58% op., 50% cons.) patients. A relevant restriction in the range of motion in the ankle joint was found in 26 (65%; 76% op., 58% cons.). In 23 patients (62%; 65% op., 59% cons.) the radiological evaluation revealed a grade 1 degree arthritis of the ankle joint, in the talonavicular joint in 17 patients (42.5%; 41% op., 45% cons.), and in the calcaneo-cuboid joint in 14 patients (35%; 47%., 27% cons.). The statistical analysis revealed a better outcome in the operative group compared with the conservative group, although the operated os calcis fractures in the majority were the more severe fracture types. In all evaluation systems a score between 61 and 69 points could be achieved with no significant difference between the operatively and conservatively treated groups and between the newly developed questionaire and the clinical-radiological scoring systems. For the questionaire this fulfills the requirements for a reliable outcome evaluation.

Adult↗
PubMed1999

[The value of CT in classification and decision making in acetabulum fractures. A systematic analysis].

UNLABELLED: The classification of acetabular fractures and especially the diagnosis of additional lesions can be misleading, when the personal experience is limited and the decisions are based only on conventional radiographs. The introduction of Spiral-CT with multiplanar reformations and 3-D views has improved the quality of visualization. Due to their higher costs, the need of these additional diagnostic tools is frequently questioned. This paper discusses the relevance of plain radiographs, 2-D-CTs, 3-D-CTs and Femursubtraction-CTs (FsCT) for the classification of acetabular fractures, based on a controlled study. METHODS: Thirty physicians with different levels of experience in acetabular surgery were divided in three groups of 10 each: group I comprised residents without operative experience in acetabular surgery, group II was physicians with 3-10 years of operative experience, and group III was experts in acetabular surgery. A total of 10 complete radiographic cases of high quality providing all levels of preoperative diagnostics (plain radiographs, 2-D-CT, CT with multiplanar reformation, 3-D-CT, Fs-CT) of different acetabular fracture types were prepared. The task for each candidate was to classify the fracture according to Letournel and to identify all additional injuries within the hip joint (e.g. marginal impaction, head fractures, etc.). The different diagnostic "levels" could be ordered stepwise according to personal need and no time limit was given. The case was finished when the candidate presented his final diagnosis. The use of the different radiographs, the preliminary diagnosis, the changes in diagnosis, and the final decisions were recorded. These findings were correlated with the different levels of experience and against a "consensus classification" which was generated by thorough discussion, and the use of intraoperative information and postoperative radiographs not accessible to the candidates. RESULTS: The "correct" fracture classification based on plain radiographs was: group I, 11%; group II, 32%; group III, 61%. Based on 2-D-CT a "correct" diagnosis was reached by 30% in group I, by 55% in group II, and by 76% in group III. With consideration of the "transient forms" in acetabular fractures based on Letournel and the 3-D-CT used mainly by group I, the rate of "correct" classifications rose to 65% in group I, 64% in group II and 83% in group III. The modifiers were diagnosed "correctly" in group I by 37%, in group II by 56%, and in group III by 73%. The use of the 3-D-CT and especially the Fs-CT by group I resulted in an improvement in the rate of correct classifications to 61%, whereas in group II the Fs-Ct was used only exceptionally. The 2-D-CT was the basis for the diagnosis of the additional lesions in acetabular fractures within all groups resulting in 73% complete diagnoses in group III. This study showed the importance of CT for the exact analysis and classification of acetabular fractures. In particular, the secondary reformations in CT and the 3-D-views dramatically improved the rate of "correct" classifications in the group of surgeons with limited personal experience in acetabular surgery. This allows the less experienced an acceptable level of "correct" diagnoses, so that the treatment options can be weighed correctly. Among the "experts" a rate of divergent classifications of approximately 20% was observed, especially in "transient" forms of acetabular fractures.

Acetabulum↗
PubMed1999

[Treatment of intraarticular calcaneal fractures in adults. A treatment algorithm].

Significant progress has been made in terms of the management of calcaneal fractures. This is reflected in the marked decrease in complication rates associated with the current intervention of these potentially devastating injuries. The treatment priorities that, in the authors opinion, are key to achieve best results in a displaced calcaneal fracture are anatomic reconstruction of the entire calcaneus: articular surfaces, height, alignment, and length, with a function directed postoperative management. The value of these priorities are confirmed by the authors longterm follow-up results as presented here. To reemphasize, conservative treatment should be considered only in cases of extraarticular fractures, minor displaced intraarticular fractures in nonambulatory patients, and in cases where there is a clear contraindication for surgery. Regarding the technical requirements for an anatomic reconstruction, the os calcis fracture should be categorized as a procedure for experts. In two-part fractures, according to the Sanders classification, an anatomical reduction is obtainable in more than 80%-90% of cases. However, in consideration of the articular cartilage damage, a 70% rate of good to excellent clinical results seems realistic. In three-part fractures, anatomic reduction is attainable in about 60% of cases with a 70% rate of good results. These two subgroups comprise about 90% of all calcaneus fractures. It is the authors recent experience to optimize the extended lateral approach using posteromedial and anterolateral windows, so that an anatomic reduction in more than 60% of Sanders Type III os calcis fractures can be achieved. Further scientific work in this area of trauma orthopedics would benefit most from a general consensus on a fracture classification system and on a clinical scoring system, with 5 year follow-up studies using these treatment methods and evaluation systems.

Adult↗
PubMed1999

Long-term results of subtalar fusions after operative versus nonoperative treatment of os calcis fractures.

From 1984 to 1994, 40 patients with a subtalar fusion were reexamined in long-term follow-up. The evaluation of the overall results was carried out with three different scoring systems. The calcaneal fractures were primarily treated nonsurgically in 23 patients (57.5%), and 17 patients (42.5%) had undergone ORIF. Complete pain relief was achieved in 52.5% of patients; 65% revealed a restriction in a range of motion in the ankle joint, and in 62% a grade 1 arthritis of the ankle joint was found. The statistical analysis could only reveal a tendency for a better outcome in the operative group compared with the nonsurgical group, although within the operated group, the majority of the os calcis fractures were more severe than in the nonsurgical group.

Adult↗
PubMed1998

[Fractures of the pediatric foot].

Some 13% of fractures in children are in the foot. Of these fractures, 50% involve the metatarsals and the phalanges. These are treated conservatively and do not cause therapeutic problems in general. In contrast, fractures and dislocations of the midfoot and hindfoot occur very rarely, so profound therapeutic expertise is lacking. The present paper takes stock and provides a critical assessment of the therapeutic concepts presented hitherto and new approaches to different problematic fractures. The long-term results of the literature and our own follow-up of dislocated intraarticular talus and calcaneus fractures which were not reduced anatomically has shown important problems in terms of pain, limited range of motion and malalignment in adolescence. In contrast to the findings in adults, no arthrosis was apparent in the radiological examinations. The findings were similar in mishealed Chopart dislocation and Lisfranc dislocation. The treatment of complex foot trauma is a multidisciplinary team approach. These challenging injuries should be treated only in centers where vascular and plastic surgeons are constantly available. The precise scientific assessment of foot fractures in children is confronted with the problem that so far too few cases have been evaluated. Rare problematic fractures (i.e. talus, calcaneus) require scientific work-up to establish a "gold standard" for operative and conservative treatment. This can only be accomplished in a multicenter study.

Adolescent↗
PubMed1998

[Internal osteosynthesis after unstable pelvic ring fracture in a 3-year-old child].

A 3-year-old child was trapped under the heavy load of a forklift truck and sustained an unstable pelvic ring fracture (Tile type C) with complete SI disruption, disruption of the public symphysis and external rotation injury of the contralateral SI joint. An immediate internal fixation was performed, exposing the SI joint and the public symphysis simultaneously. For stabilization an H-plate was used for anterior plate fixation of the SI joint, while the public symphysis was stabilized by screws and cerclage wires. After one revision of the symphysis the clinical course was uneventful with anatomical healing of the pelvic ring. The implants were removed after 4 months. Clinical and radiological follow-up after 12 months showed no signs of maldevelopment of the pelvic ring.

Bone Plates↗
PubMed1998

Management of calcaneal fractures in adults. Conservative versus operative treatment.

Significant progress had been made in the management of calcaneal fractures. This is reflected in the marked decrease in complication rates associated with the current intervention of these potentially devastating injuries. The treatment priorities that are key to achieve best results in a displaced calcaneal fracture are an anatomic reconstruction of the entire calcaneus including articular surfaces, height, alignment, and length, with a function directed postoperative management. The value of these priorities is confirmed by long term followup results. Conservative treatment should be considered only in cases of extraarticular fractures, in cases of minor displaced intraarticular fractures in patients who are nonambulatory, and in cases where there is a clear contraindication for surgery. An anatomic reconstruction of an os calcis fracture is difficult to obtain. In two-part fractures, according to the classification described by Sanders et al, an anatomic reduction is obtainable in more than 80% of cases. However, if the articular cartilage damage that is typically present is considered, a 70% rate of good to excellent clinical results is more realistic. In three-part fractures, anatomic reduction is attainable in approximately 60% of cases with a 70% rate of good results. These two subgroups comprise approximately 90% of all calcaneal fractures. It has been put into practice recently to optimize the extended lateral approach using posteromedial and anterolateral windows, so that an anatomic reduction can be achieved in more than 60% of os calcis fractures considered as Type III according to the classification described by Sanders et al. Additional scientific work in this area of trauma orthopaedics would benefit most from a general consensus on a fracture classification system and on a clinical scoring system, with 5-year followup studies using these treatment methods and evaluation systems.

Algorithms↗
PubMed1997

[Coincidence of bone infarct and aggressive bone metastasis].

A 42-year-old male patient presented with a history of persistent pain in the right femur without trauma of 2 months, duration and an episode of bloody stools 3 months earlier with no clinical findings upon examination. X-rays and CT scan revealed a circumscribed lesion with sclerosis and periostal reaction in the right proximal femur. A three-phase bone scan showed a massive hot spot in this area. Primarily differential diagnoses included a Brodie's abscess and/or a tumor. An excisional biopsy of the area was performed and revealed the coexistence of a bone infraction and the metastasis of an adenocarcinoma of unknown origin. The lesion in the bone was resected, filled with autogenous cancellous bone and stabilized with a plate. Further intensive screening with CT of the abdomen, gastroscopy and colonoscopy led to the primary tumor, an adenocarcinoma at the rectosigmoidal junction. No other metastases were detected. This patient presented with severe pain an radiologically divergent findings: a presumably benign process on radiography, but a massive hot spot on scintigraphy. Further procedures such as a CT scan and/or MRI had to be undertaken. If the analysis includes the differential diagnosis of a malignant process, a biopsy must be obtained, and if this reveals a metastasis, the primary tumor must be sought.

Adenocarcinoma↗
PubMed1996

[The dynamic hip screw with support plate--a reliable osteosynthesis for highly unstable "reverse" trochanteric fractures?].

ORIF management of unstable trochanteric fractures of type A3 of the A0 classification is difficult because of lateral dislocation of the proximal fractured segments, particularly when only the sliding hip-screw is used for fixation. A connectable butt-press plate was recently developed in order to prevent this type of dislocation. We review the results with this fixation technique in 22 elderly patients with an average age of 76 years who presented with highly unstable trochanteric fracture of the A3 type. Three patients died of diseases unrelated to the trauma or operation before the fractures had healed. The other 19 were followed prospectively until fracture healing had occurred. Complaints, leg shortening and changes in the CCD angle were recorded. Furthermore, the mobility score was determined. Although the patients were able to bear full weight after the operation, no lateral dislocation of fragments was observed. Only 1 patient had a varus dislocation of 5 degrees until the fracture had consolidated. This was due to severe osteopenia and subsequent dislocation of the screw within the femoral head. No pseudarthrosis, osteitis or rotational malalignment was noted. Five of the surviving patients had a lower mobility score after fracture healing as compared to the status before the fracture was sustained. On the basis of this review, we recommend the use of this new connectable buttress plate with sliding hip screws because it provides sufficient fixation of highly unstable fractures of type A3.

Aged↗