Biomedical subjects
H Tscherne
Publications and source records attributed to H Tscherne.
[Fractures of the pediatric foot. "What heals during growth"?].
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[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.
[Must the accident victim be protected from the emergency physician?].
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[Must the accident victim be protected from the emergency physician?].
Quality control in preclinical medical care has become a matter of concern in recent years. In order to evaluate the quality of treatment one has to set standards. Most of the current standards were defined by different preclinical care organisations and are also accepted in the unique emergency medical care protocol used in the Federal Republic of Germany. Considering these standards, we retrospectively analyzed the preclinical treatment of all multiple trauma patients admitted to our department between 1985 and 1996. The major issues of this analysis were the diagnoses, the indications for invasive measures and the performance. Regarding the triage, for example, it was noted that 28% of patients who should have been admitted to a level I trauma center considering the severity of their injury were first admitted to a level III hospital and needed to be transferred later. In 7% of patients two additional mistakes and in 4% of patients more than two mistakes in the triage were noted. On the other hand, there are records of patients who were considered to be only slightly injured but received invasive treatment. Preclinical intubation and mechanical ventilation was not performed in 16.5% although the severity of injury clearly demanded it. A thoracic drain tube was not positioned in 38% of patients suffering from severe thoracic trauma (AISThorax > or = 4). Insufficient application of resuscitation volume (< 2500 ml on admission) was evident in 17% of all documented patients. According to our results, the initial evaluation of severity of injury is still a major problem and leads to wrong decisions for treatment. Although the qualification of ambulance physicians has been standardized for some years, there are still clear deficits in the preclinical management of trauma patients that need to be targeted.
[Elbow para-articular pseudarthrosis. Etiology and treatment].
Non-unions in the proximity of the elbow are very rare and in most cases caused by mistakes in initial treatment. Reconstruction after pseudarthrosis of the elbow continues to pose a challenge for any surgeon. The aim of our study was to analyze the initial mistakes and to underline the most important aspects of reconstructive surgery. In a retrospective study over a defined period of 10 years (1/1985 to 12/1994) we were able to treat altogether 27 non-unions in the proximity of the elbow. These patients were transferred to our hospital at an average of 44 weeks after initial therapy elsewhere. The main symptoms were in 17 cases pain and in all other patients functional deficit. Reconstructive surgery was performed an average 54 weeks after the primary injury. In 24 out of 27 cases a re-osteosynthesis, in 12 an arthrolysis, in 7 a neurolysis and in 2 cases an arthroplasty was needed. The patient could return to work an average 18 weeks after the operation and 53 weeks after injury. The initial complaints were reduced in 24 of 27 cases, with a significant improvement in the ROM and functional outcome according to the Mayo Elbow Performance Index.
[Resilience of tibial transplant fixation for replacement of the anterior cruciate ligament. Interference screws vs. staples].
The endoscopic single incision technique for ACL reconstruction with a femoral half-tunnel may lead to a graft/tunnel mismatch and subsequent protrusion of the block from the tibial tunnel. The typical tibial fixation with an interference screw is not possible in these cases. Fixation with staples in a bony groove inferior to the tunnel outlet can be used as an alternative technique. Current literature does not provide biomechanical data of both fixation techniques in a human model. This study was performed to evaluate primary biomechanical parameters of this technique compared to a standard interference screw fixation of the block. 55 fresh-frozen human cadaver knee joints of a younger age (mean age: 44 years) were used. Grafts were harvested from the patellar tendon midportion with bone blocks of 25 mm length and 9 mm width. A 10 mm tibial tunnel was drilled from the anteromedial cortex to the center of the tibial insertion of the ACL. 3 different sizes of interference screws (7 x 30, 9 x 20 and 9 x 30 mm) were chosen as a standard control procedure (n = 40). For tibial bone-block fixation the graft was placed through the tunnel, the screw was then inserted on the cancellous or the cortical surface respectively. 15 knees were used for staple fixation. A groove was created inferior to the tunnel outlet with a chisel. The bone block was fixed in this groove with 2 barbed stainless steel staples. Tensile testing in both of the groups was carried out under axial load parallel to the tibial tunnel in a Zwick-testing-machine with a velocity of 1 mm/sec. Dislocation of the graft and stiffness were calculated at 175 N load. Maximum load to failure using interference screws varied between 506 and 758 N. Load to failure using staples was 588 N. Dislocation of the graft ranged between 3.6 and 4.7 mm for interference screw fixation and was 4.2 mm for staples. With both fixation techniques, the recorded failure loads were sufficient to withstand the graft loads which are to be expected during the rehabilitation period. Staple fixation of the bone block outside of the tunnel resulted in fixation strength comparable to interference screw fixation.
[Amputation or reconstruction of IIIB and IIIC open tibial fracture. Decision criteria in the acute phase and late functional outcome].
In IIIB and IIIC type open tibial fractures (according to Gustilo) the primary decision that has to be made regarding therapy is wether or not the limb can be salvaged. To standardize the criteria for amputation different salvage scores have been established in recent years. In this study the Hannover Fracture Scale (HFS), the Predictive Salvage Index (PSI), the Mangled Extremity Severity Score (MESS) and the NISSSA score were evaluated regarding their clinical relevance. When ROC Analysis was performed for all these scores in our patients the HFS revealed the highest sensitivity (0.91), but low specificity (0.71). The highest specificity was noted for the MESS (0.97), which in parallel showed the lowest sensitivity (0.59). In general it seems to be essential to make the right decision initially in order to avoid secondary amputation. All the scores mentioned here appear to be helpful in decision making. Salvaged limbs in IIIB and IIIC fractures presented a comparable good outcome, whereas salvaged IIIC injuries with a high score presented an outcome which was as bad as in secondary amputations. Secondary amputated patients required not only significant longer hospitalization but also resulted in poor outcome compared with the patients having received reconstruction or primary amputation.
[Pediatric polytrauma. A retrospective comparison between pediatric, adolescent and adult polytrauma].
Numerous epidemiological studies about multiple trauma patients do not include an analysis of patients under the age of 18. To study this, the data of 682 patients with multiple traumata, treated between 1981 and 1991 at Hannover Medical School, Germany, were retrospectively analyzed. The patients were divided into four age-related groups: preschool age (< 6 years), school age (< 13 years), teenagers (< 18 years) and adults (> or = 18 years). Analyzed were the cause of trauma, localization of injuries and the cause of death. Children were less often injured as passengers in cars, but more often injured as pedestrians and bicyclists than adults. However, children showed a significant higher mortality than adults, with threefold increased risk of death when they injured as passengers in car accidents. In all groups injuries to the head and the legs were most common. Children showed a lower incidence of trauma to the thorax, abdomen, hip and arms than the adult group. Nevertheless, trauma to the thorax, abdomen and head was associated with the highest risk of death in all groups. Spinal cord injuries, especially injuries to the neck, also showed a high risk of death. Children younger than 6 years had the most severe head injuries. Safety improvements for children in cars, helmet usage on bicycles and early training in traffic safety for children might decrease the lethality in this group of trauma patients.
[Interim results of surgical therapy of patellar dislocation by Insall proximal reconstruction].
Between 1984 and 1991, 57 patients with diagnosis of an acute or recurrent patellar dislocation were treated operatively using proximal realignment with vastus medialis transfer and lateral release (Insall operation). A total of 45 patients (15 with acute and 30 with recurrent patellar dislocation) were reviewed at an average follow-up of 6.5 years (2-9.6 years). The average age at injury was 21.5 years, with a predominance of female patients. Follow-up examination included routine knee examination, clinical review using the modified knee scoring scale of Larsen and Lauridsen, sports activity level and subjective satisfaction. Radiographics from 27 patients (60%) were evaluated. One patient from each group suffered recurrence of patellar dislocation. All patients had stable knee joints and a full range of motion. There was no statistical difference in the pre- and postoperative sports activity level in both groups. Three patients (19.9%) with acute patellar dislocation and seven patients (23.3%) with recurrent patella dislocation had excellent results using the Larsen and Lauridsen score scale. Ten patients (66.6%) with acute and 12 (39.9%) with recurrent dislocation had good results. One patient with recurrent patellar dislocation had a fair result. Subjective evaluation revealed the operative result in 93% of cases as very good, good or satisfactory. Patellofemoral osteoarthritis was seen in 11 (40.7%) of 27 patients. Our results show good clinical results for the treatment of acute patellar dislocation in young, active patients with the proximal realignment procedure. The recurrence rate of patellar dislocation can be reduced for acute and recurrent patellar dislocation. Subjective satisfaction with this procedure is rated very good.
[Endoscopic versus limited open technique for replacement of the anterior cruciate ligament. 4 years outcome of a prospective study].
ACL reconstruction with patellar tendon graft has become a standard procedure. The graft can be inserted either using two tunnels and a lateral femoral incision or with a femoral half tunnel drilled from the joint, thus avoiding the lateral incision. Advantages of the single-incision technique in the early rehabilitation period have been claimed. 40 patients with ACL deficiency were included in a prospective randomized trial comparing single and two-incision technique with a follow-up period of 4 years. Preoperative data did not show any significant difference between the two groups. At follow-up no difference were observed with respect to complications or he progress of rehabilitation. Evaluation after 1 and 4 years according to the IKDC form revealed good to excellent results in 70% of all patients. The Tegner-score increased significantly, however most patients did not regain their former activity level. ACL-reconstruction reduced anterior translation of the knee significantly at 6 months follow-up. However, we observed a slight increase of anterior translation after 1 and 4 years in both groups; stability was comparable in both groups at all time periods. We conclude that an arthroscopic single-incision technique has no advantage compared to a mini-open two-incision technique for ACL reconstruction with patellar tendon graft in terms of subjective or objective parameters.
[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.
[Can knee joint proprioception by reconstruction of the anterior cruciate ligament be restored? A prospective longitudinal study].
Knee proprioception was assessed in 20 healthy volunteers, 10 patients with acute anterior instability and in 20 patients with chronic anterior instability preoperatively as well as after 3 and 6 months postoperatively. To determine proprioception, an angle reproduction test was performed. There were no differences between the right and the left knee joint or between men and women. Best proprioception was measured near full extension. The acute trauma causes massive damage of the proprioception, which could be improved significantly by rehabilitation. However, rehabilitation could not restore proprioception. 3 months postoperatively, there was a slight decrease of proprioception as compared to the preoperative values, but 6 months after reconstruction, restoration of proprioception was documented near full extension and full flexion. In the mid range position, the proprioception could not be restored. There was no difference between open and arthroscopic techniques. The highest correlation was found between proprioception and patient's satisfaction.
[Comparison of a radiation-independent aiming system and free-hand technique for distal locking of unslotted femoral nails].
Although the free-hand technique remains the most popular method for distal interlocking screw insertion, proximally mounted "radiation-independent" devices which compensate for implant deformation recently have been developed for rotationally stiff, unslotted femoral nails. However, the benefits of such systems have not been determined. This study prospectively compared the duration of the nailing procedure, the length of radiation time, and the accuracy of interlocking screw placement with a radiation-independent distal aiming system to those using the free-hand technique. In twenty paired intact cadaveric femora, a single surgeon experienced only in the free-hand technique performed statically locked intramedullary nailing using the two methods. For the aiming system and free-hand technique respectively, the total operation time was 19.1 +/- 8.4 versus 20.9 +/- 11.3 minutes (p = 0.9), the distal locking time was 6.6 +/- 2.4 versus 4.8 +/- 1.5 minutes (p = 0.002), the total fluoroscopy time was 23 +/- 17 versus 69 +/- 34 seconds (p < 0.0001), and the distal locking fluoroscopy time was 0 versus 37 +/- 15.5 seconds (p < 0.0001). There were no failures in either group. Drill nail contact (p < 0.0001) and distal screw damage (p = 0.02) were both greater with the free-hand technique.
[Complex injuries--complex treatment algorithms].
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Multiple organ failure (MOF) after severe trauma--a sheep model.
OBJECTIVE: To perform a reproducible long-term (10 days) large animal model of multiple systems organ failure without necessity of a continuous stimulus. DESIGN: Adult female merino sheep submitted to a 5-day stimulation period followed by a 5-day observation period. Day 1: Hemorrhagic shock was combined with a traumatic surgical insult (reamed intramedullary femoral nailing), followed by serial administrations every 12 h for 5 days of a combination of endotoxin and zymosan activated plasma. Organ function was followed for 5 further days. RESULTS: Cardiac index increased significantly during the study (day 1: 491 +/- 8 mm Hg; day 10: 427 +/- 20, p < 0.05). Liver function was impaired and bilirubin levels increased significantly (day 1: 2.9 +/- 0.3 micromol/l; day 10: 7.2 +/- 0.9; p < 0.05). Creatinine clearance decreased initially (day 1: 54 +/- 7 ml/min), increased to a peak on day 2 (104 +/- 27), and then deteriorated again (day 10: 53 +/- 18). CONCLUSION: This new large animal model of trauma-induced MOF is reproducible and may be suitable for the study of new therapeutic approaches to therapy.
A new mechanical aiming device for the placement of distal interlocking screws in femoral nails.
Although the free-hand technique remains the most popular method for distal interlocking screw insertion, a proximally mounted "radiation-independent" device which compensates for implant deformation has been developed. In 15 intact human cadaveric femora the same surgeon performed statically locked intramedullary nailing using the distal aiming system. Operation time, distal screw insertion, total radiation time and accuracy of the interlocking screw placement were measured using a radiation-independent distal aiming system. The average total operation time was 21.2+/-8.6 min, and the average distal locking time (2 screws) was 7.1+/-2.4 min. The total operation time and the distal locking time declined over the first 10 cases. These times did not significantly improve in the subsequent 5 procedures. The average total fluoroscopy time was 28.1+/-16.6 s. None of the screw placements using the distal aiming device required the use of fluoroscopy. Drill-nail contact was absent in 5 drillings, mild in 9 drillings, moderate in 16 drillings, and severe in none. Measurement of screw damage showed in 55 of 60 measurements wear of less than 15 microm. There were no failures or major complications. A minor complication related to distal locking was observed in one specimen. This study suggests that distal interlocking screws can be placed successfully using a radiation-independent aiming arm-based system, which accounts for nail deformations. The distal aiming device (DAD) can be learned easily. The main advantages of the aiming arm include the elimination of radiation during distal interlocking and precise screw placement with little insertion-related hardware damage.
Effects of percutaneous and conventional plating techniques on the blood supply to the femur.
A cadaveric arterial injection study was performed to study the effects of percutaneous and conventional surgical plating techniques on femoral vascularity. Sixteen-hole dynamic condylar screw and condylar buttress plates were applied on the proximal and distal shafts, respectively, of intact femora in ten human cadavers. On one side, the plate was inserted using a lateral conventional plate osteosynthesis (CPO) technique with elevation of the vastus lateralis muscle to expose the shaft. On the contralateral side, the plate was inserted percutaneously beneath the muscle using a minimally invasive plate osteosynthesis (MIPPO) technique. After plating, blue silicone dye was injected through the common femoral artery. A dissection was then performed to identify the femoral perforating arteries (PAs). The pattern of periosteal filling of the injected dye was analyzed. The MIPPO technique maintained the integrity of the PAs and exhibited superior periosteal perfusion. The results of this study indicate that the MIPPO technique maintains femoral vascularity and perfusion better than the CPO technique.