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Biomedical subjects

H Tscherne

Publications and source records attributed to H Tscherne.

At least 127 records · Page 7Linked to original sources
PubMed1997

A new technique for the distal locking of solid AO unreamed tibial nails.

Proximally mounted distal aiming systems have failed primarily because of nail deformation during insertion. A mechanical aiming device for the insertion of distal locking screws for solid unreamed AO tibial nails was developed and was tested in twenty unreamed solid tibial nailing procedures in a video-documented prospective clinical study. The rate of accurate screw placement, time expended, complications, and outcome for each patient were recorded. Distal locking was performed successfully in all cases without image intensification. Although a high percentage (55%) of fractures were open, the total mean operative time was 108 minutes (range, 60 to 180 minutes) and the mean time for distal locking (three screws) was 15.5 minutes (range, 8.0 to 39.0 minutes). Notable drill-nail contact occurred in 15 percent of the distal screws placed, demonstrating accurate aiming and drilling. There were no major intra- or postoperative complications related to the distal aiming system.

Adolescent↗
PubMed1997

Treatment algorithm of chronic ankle and subtalar instability.

From 1981 to 1984, 131 reconstructive procedures and 113 Evans tenodesis procedures (1972-1984) were performed for patients with chronic instability of the ankle joint. From 1981 to 1985, 42 Christman/Snook procedures were performed for patients with isolated or combined subtalar instability. Reevaluation was conducted for 223 patients (102 reconstructive procedures, 87 Evans tenodesis procedures, and 34 Christman/Snook tenodesis procedures). The follow-up protocol comprised standard and stress radiograms, subjective patient evaluation, and objective functional data. No patient in either treatment group had clinically important ankle instability. Patients who had undergone the Evans tenodesis had a 3.3 degrees mean less talar tilt than did patients treated with reconstructive procedure. Of 87 patients who underwent Evans tenodesis, 33 had a mean supination deficit of 7.5 degrees. According to the +/- 100 points classification, 90% of the patients in both groups achieved good or excellent results. For subtalar instability, the Christman/Snook techniques resulted in a mean supination deficit of 7.2 degrees in 20 patients. Of 34 patients, 31 were rated good or excellent.

Algorithms↗
PubMed1997

Recurrent rotational deformity of the femur after static locking of intramedullary nails: case reports.

Rotational deformity following intramedullary nailing may cause symptoms and require surgical correction by osteotomy. Reamed, locked intramedullary nailing may be performed, but concern about cortical blood supply and potential pulmonary dysfunction from reaming have led many surgeons to limit this and use smaller diameter nails. Slotted nails are commonly used but are less stiff in torsion than the newer unslotted nails, particularly at the lower diameters. We report two cases of recurrent femoral rotational deformity after using statically interlocked slotted intramedullary nails to correct existing femoral rotational deformities. These patients show that small diameter statically interlocked femoral nails with diminished bone-nail contact must be stiff enough in rotation to avoid potential recurrence.

Adult↗
PubMed1997

Superior results of tibial rodding versus external fixation in grade 3B fractures.

From 1987 to 1993, 41 Grade 3B open tibial shaft fractures were treated with the unreamed tibial nail or an external fixator. The method of treatment was left to the choice of the operating surgeon. Three below knee amputations were performed; three patients died; and three were lost to followup. Thirty-two patients were observed until union or for at least 1 year. There were no significant statistical differences between the two groups with respect to fracture type, fracture location, age, gender, or accompanying injuries. The unreamed tibial nail group showed significantly better results regarding time to full weightbearing, number of reoperations, isolated bone grafting, walking range, and average Karlström and Olerud score. Time to bony union, infection, and nonunion were not significantly different between the groups.

Adult↗
PubMed1997

[New developments in stabilization of dia- and metaphyseal fractures of long tubular bones].

Nail, plate and external fixator are since decades the most frequently and stabilizers for the surgical treatment of dia- and metaphyseal fractures. These elements are still present today. However, there were important changes in recent years. Together with better knowledge and understanding of fracture healing, fracture biology, implant metallurgy and mechanics and a more and more specified application of these techniques, this resulted in improved possibilities for the treatment of injured patients. Beside an overview about the current discussion of unreamed and reamed nail insertion new trends, techniques and nails are presented for the different long bones (retrograde nails, spiral blade, flex-nail humerus and a distal aiming device (DAD) for interlocking screws). In addition, new approach techniques for nailing (stab incision) and minimally invasive percutaneous plate osteosynthesis (MIPO) for metaphyseal fractures of the proximal and distal femur and proximal tibia are described including the necessary techniques for control of axes and rotation.

Bone Nails↗
PubMed1997

[Biomechanics of femoral interlocking nails at the bone-implant transition].

Today there is a variety of different interlocking intramedullary nail designs available for the femur-each designed with a different approach to achieve stability for fracture fixation. We compared different nail types in the bone-implant complex (BIC) of four unreamed solid nails and a slotted, reamed nail to see if there are major differences in stiffness for axial load, bending and torsion. We simulated comminuted mid-shaft fractures by a 2 cm defect osteotomy in paired human cadaver femora. Each bone was tested intact in a Universal testing machine. The results were recorded, osteotomy and osteosynthesis were performed, and the BIC was tested. Relative stiffness was calculated for each individual bone. For P-values less than 0.01 ('least significance difference test') the difference between groups was considered to be significant. In torque testing the unslotted solid nails showed significantly more stiffness (0.6-1.8 Nm/degree) compared to the slotted nail (0.2 Nm/degree). Compared to intact bone (6.9 Nm/degree), both groups of nails were significantly less stiff (relative stiffness 2-20%). In axial load and bending testing, the large-diameter unreamed nail showed greater higher stiffness (32-68%). This study shows that stiffness of the BIC in interlocking femoral nails is more dependent on nail profile than on the press-fit of nails in the medullary canal. For torque stiffness the absence of a slot is of special importance. According to our study, all of the unslotted nails tested give adequate stability for fracture fixation.

Adult↗
PubMed1997

[Functional, neuropsychological and social outcome of polytrauma patients with severe craniocerebral trauma].

The aim of this study was to identify, in (pre-) clinically obtained data, parameters predicting the outcome of patients with multiple trauma and severe head injury. Fifty-eight patients aged 27 +/- 10 years were investigated an average of 5.8 years after the accident. The Hanover Polytrauma Score was 34 +/- 11 points, the initially assessed Glasgow Coma Scale (GCS) was 6.2 +/- 3.2 points; and the duration of coma was 15.4 +/- 14.4 days. The primary length of stay in hospital averaged 33.4 days, including 22.9 days in the intensive care unit and 20.2 days of ventilation. For a further 223 days the patients were treated at the Neurologic Clinic of Hessisch Oldendorf. Besides different neurologic deficiency symptoms, the psychometric tests showed deficits in all areas. In particular, information processing speed, concentration, recent memory and learning performance were impaired. There was free mobility of all joints in 33% of the patients. Due to injury the elbow and ankle joint developed the worst restriction. Central paralysis and heterotopic ossification also caused a restriction in joint mobility. Half of the patients were confronted with different social changes. The rate of return to work was dependent on age. Some 42% of all patients had taken up their former profession, 5% were still in training or at college, 32% were retrained to other professions, 16% were unemployed and 5% were completely retired on pension. Age, injury severity, GCS, duration of coma and duration of weaning were suitable predictors in correlation- and regression analysis. The Glasgow Outcome Scale showed good recovery and moderate disability in 53%, severe disability in 33% and persistent vegetative state in 14% of the patients.

Activities of Daily Living↗
PubMed1997

[Complex trauma of the elbow].

The complex injury is characterized by a fracture and/or dislocation of the elbow in association with a serial injury of the upper extremity, or a severe soft tissue trauma, or a prolonged ischemia caused by vascular injury or compartment syndrome. They are defined as complex injuries because their treatment differs from that of a simple fracture implying that standardized concepts usually cannot be employed. The results of primary treatment show a high rate of complications. They are accompanied by functional deficits including pseudarthrosis and ankylosis. As a consequence, ulnar neuropathy may occur. Inadequate treatment leads to delayed rehabilitation and several secondary operations. The main goal points at the reconstruction of the elbow joint to restore function. Therefore, the logistical pathway of individual therapy is the key for success. The operation has to include fracture stabilisation of all injuries of the upper extremity. Only stable osteosynthesis makes early mobilisation possible. Transfixation of the elbow joint should be reserved for exceptional cases. The principals of AO have proven to be practical both for the distal humerus and the proximal forearm. Successful reconstruction of the elbow joint often demands extended approaches. ORIF of the proximal ulna can be achieved by indirect reposition techniques. Dynamic stabilisation should be established by conservation of the radial head and coronoid process. For treatment of soft tissue injury it is necessary to undertake local reconstructive measures. Operative treatment is widely indicated for forearm compartment syndrome. Diagnosis and therapy of possible accompanying vascular injury should be made early to avoid prolonged ischemia. Operative treatment of nerve injury is only indicated in case of sharp dissection of the nerve. Otherwise the reconstruction should be performed, but not earlier than three months. Rehabilitation outcome depends on primary therapy. Sufficient functional results are only achieved after early mobilisation and intensive physiotherapy. If necessary, arthrolysis is planned early and combined with removal of implants at 6 months post injury.

Compartment Syndromes↗
PubMed1996

The morphological effects of synthetic augmentation in posterior cruciate ligament reconstruction: an experimental study in a sheep model.

The treatment of posterior cruciate ligament (PCL) injuries remains controversial. Due to various problems, PCL reconstruction has not consistently produced the knee stability desired. Biological graft tissue undergoes a remarkable healing process comprising different phases. The strength of autogenous graft material decreases soon after operation. During this early healing phase synthetic augmentation could protect the graft tissue from overloading or overstretching, supporting the tissue revitalization and remodeling process. In order to evaluate the morphological effects of the ligament augmentation device (LAD) on a free patellar tendon autograft in PCL reconstruction, a comparative study in sheep was conducted. In 24 mature sheep, the PCL was replaced with either a patellar tendon autograft alone or a patellar tendon autograft augmented by the LAD. The LAD was fixed at both ends. After the operation the animals were not immobilized. Tibial fixation was released 8 weeks postoperation. The autografts of both groups were histologically evaluated after 2, 6, 16, 26, 52, and 104 weeks. In addition to necrotic and degenerative alterations, a remarkable inflammatory reaction could be seen in the LAD-augmented autografts early postoperation. Compared with the nonaugmented autografts, tissue formation and remodeling were delayed in the augmented group. After 1 and 2 years, the morphology of the autograft tissue was similar in both the augmented and nonaugmented group and differed from that of a normal PCL. The LAD was surrounded by a chronic inflammatory reaction, and collagen fiber ingrowth into the LAD was not observed. Using transmission electron microscopy, small diameter collagen fibrils were predominant in the graft tissue of both groups. Thus, a better remodeling of the autograft tissue in the presence of the LAD could not be demonstrated in this particular study. The value of synthetic augmentation of biological grafts in PCL reconstruction seems to be questionable at present.

Animals↗
PubMed1996

[Complex trauma of the knee joint. Diagnosis--management--therapeutic principles].

The complex nature of combined fractures and soft tissue injuries of the distal femur and proximal tibia needs special attention and specific management. Distal femoral and proximal tibial fractures in young patients are usually caused by high-energy trauma. They are complicated by a high rate of systemic and local injuries to cartilage, ligaments and skin. This small but important group with severe injuries needs a detailed treatment algorithm, because despite the treating surgeon's skill, enthusiasm and wishful thinking, these injuries frequently lead to unsatisfactory results. The combination of distal femoral fractures and proximal tibial fractures was defined as complex knee injury type 1; the combination of distal femoral fractures or proximal tibial fractures with second or third degree open or closed soft-tissue injury was defined as complex knee injury type 2; knee dislocations were defined as complex knee injury type 3. A decision-making scheme is presented specifically addressing timing and treatment modalities. Out of 116 type 1 and 2 complex knee injuries, 8 had a deep infection, in 6 cases an amputation was carried out and in 4 cases a knee arthrodesis was performed. In 81 isolated distal femoral fractures, only 4 had a deep infection, none needed amputation, and in only 1 case did a knee arthrodesis have to be performed. The average Neer Score in 90 followed-up complex knee injuries, types 1 and 2, was 76.5 +/- 13.5 compared with 82.8 +/- 10 (out of 54 isolated distal femoral fractures). Out of 37 cases with knee dislocation, 22 (60%) had an poor result according to the Lysholm Score (average Lysholm Score 60.7 +/- 28).

External Fixators↗