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S Hankemeier

Publications and source records attributed to S Hankemeier.

13 recordsLinked to original sources
PubMed2006

Navigated open-wedge high tibial osteotomy: advantages and disadvantages compared to the conventional technique in a cadaver study.

High tibial osteotomy (HTO) is an established therapy for the treatment of symptomatic varus malaligned knees. A main reason for disappointing clinical results after HTO is the under- and overcorrection of the mechanical axis due to insufficient intraoperative visualisation. Twenty legs of fresh human cadaver were randomly assigned to navigated open-wedge HTO (n=10) or conventional HTO using the cable method (n=10). Regardless of the pre-existing alignment, the aim of all operations was to align the mechanical axis to pass through 80% of the tibial plateau (beginning with 0% at the medial edge of the tibial plateau and ending with 100% at the lateral edge). This overcorrection was chosen to ensure a sufficient amount of correction. Thus, the medial proximal tibia angle (MPTA) increased by 9.1+/-2.9 degrees (range 5.2 degrees -12.3 degrees ) on the average after navigated HTO and by 8.9+/-2.9 degrees (range 4.7 degrees -12.6 degrees ) after conventional HTO. After stabilization with a fixed angle implant, the alignment was measured by CT. After navigated HTO, the mechanical axis passed the tibial plateau through 79.7% (range 75.5-85.8%). In contrast, after conventional HTO, the average intersection of the mechanical axis was at 72.1% (range 60.4-82.4%) (P=0.020). Additionally, the variability of the mean corrections was significantly lower in the navigated group (3.3% vs. 7.2%, P=0.012). Total fluoroscopic radiation time was significantly lower in the navigated group (P=0.038) whereas the mean dose area product was not significantly different (P=0.231). The time of the operative procedure was 23 min shorter after conventional HTO (P<0.001). Navigation systems provide intraoperative 3-dimensional real time control of the frontal, sagittal, and transverse axis and may increase the accuracy of open-wedge HTO. Future studies have to analyse the clinical effects of navigation on corrective osteotomies.

Adult↗
PubMed2006

Computer-assisted analysis of lower limb geometry: higher intraobserver reliability compared to conventional method.

Exact radiographic evaluation of lower limb alignment, joint orientation and leg length is crucial for preoperative planning and successful treatment of deformities, fractures and osteoarthritis. Improvement of the accuracy of radiographic measurements is highly desirable. To determine the intraobserver reliability of conventional analysis of lower extremity geometry, 59 long leg radiographs were randomly analyzed 5 times by a single surgeon. The measurements revealed a standard deviation between 0.36 degrees and 1.17 degrees for the angles mLPFA, mLDFA, MPTA, LDTA, JLCA and AMA (nomenclature according to Paley), and 0.94 mm and 0.90 mm for the MAD and leg length, respectively. Computer-assisted analysis with a special software significantly reduced the standard deviation of the mLDFA, MPTA, LDTA, JLCA (each p < 0.001), AMA (p = 0.032) and MAD (p = 0.023) by 0.05-0.36 degrees and 0.14 mm, respectively. Measuring time was reduced by 44% to 6:34 +/- 0:45 min (p < 0.001). Digital calibration by the software revealed an average magnification of conventional long leg radiographs of 4.6 +/- 1.8% (range: 2.7-11.9%). Computer-assisted analysis increases the intraobserver reliability and reduces the time needed for the analysis. Another major benefit is the ease of storage and transfer of digitized images. Due to the varying magnification factors on long leg radiographs, the use of magnification markers for calibration is recommended.

Adult↗
PubMed2005

Influence of cyclic mechanical strain and heat of human tendon fibroblasts on HSP-72.

Heat shock protein 72 (HSP-72) is a member of a superfamily of different proteins that are synthesized as a cytoprotective response following cellular stress. Mechanical strain is an important component in ligament and tendon healing. Up to the present point of time, the influence of mechanical strain on the expression of HSP-72 is unknown. Tendon fibroblasts from the patellar tendons of nine individuals were isolated and amplified in vitro. First, the effect of 15 or 60 min of heat exposition was studied immunohistochemically and by Western blotting. In a second experiment, the effects of 15 and 60 min of cyclic longitudinal stretching were investigated. Samples were taken after 2, 4 and 8 h. The heat exposition experiments indicate that HSP-72 accumulates in the nucleus and that there is a transient upregulation. This effect is more prominent after 60 min of heat exposure. The same reaction was found after stretching stimulation, however, to a lesser extent. There was a transient up regulation of HSP-72 after short-term stretching and a biphasic increase after 60 min of stretching. Upregulation of HSP-72 by heat and mechanical stress is a response in human fibroblasts which involves a nuclear translocation. The response differs with regard to the time points beyond 2 h after the application of either stress.

Adolescent↗
PubMed2005

[Indication for removal of tibial nails].

BACKGROUND: Tibial nail removal has been suggested as a routine procedure for both symptomatic and asymptomatic patients. The aim of this study was to define guidelines for the removal of tibial nails. PATIENTS AND METHODS: A retrospective study on the isolated removal of 69 tibial nails after fracture consolidation was done. A review of the patient charts and radiographs was performed. Forty-four patients (64%) were available for the follow-up interview. RESULTS: Preoperatively, 26 patients (59%) had local complaints. Of these 26 patients, 73% reported an improvement, and 8% reported an aggravation of their local complaints. Of the 18 patients who were asymptomatic before surgery, 17% reported long-term complaints at follow-up. CONCLUSION: We conclude that routine removal of tibial nails should be discussed critically in asymptomatic patients.

Adolescent↗
PubMed2005

Single lateral locked screw plating of bicondylar tibial plateau fractures.

We prospectively followed a case series of 68 patients with 69 AO/ASIF 41-C-type fractures treated with the Less Invasive Stabilization System for the proximal lateral tibia. We assessed malreduction, secondary loss of reduction, and infection rates in patients with a locked screw plate for unilateral fixation of bicondylar fractures. Sixty-two (91%) patients returned for final followup (range, 11-13 months). Malreduction and malalignment were defined as an intraarticular step-off of 2 mm or greater, or as a malalignment in the frontal or sagittal plane greater than 5 degrees . Fourteen fractures were open. Primary bone grafting was done in 13 patients. Significant malreduction was seen in 16 patients. There were four superficial infections and one deep infection. One fracture did not heal, and nine patients had substantial loss of reduction. Unilateral locked screw plating is a good alternative for treatment of problematic fractures of the tibial plateau that are associated with soft tissue damage and metaphyseal comminution. The reduction technique for exact alignment is demanding.

Adolescent↗
PubMed2004

Effects of cyclic longitudinal mechanical strain and dexamethasone on osteogenic differentiation of human bone marrow stromal cells.

The aim of the study was to investigate the effect of cyclic mechanical strain on differentiation markers in the presence or absence of dexamethasone. Human bone marrow stromal cells (BMSC) from seven donors (32.5+/-6.2 years) were cultivated with (D+) or without (D-) dexamethasone. A cyclic mechanical strain with an elongation of 2% (D+2; D-2) or 8% (D+8; D-8) was applied for three days with a stimulation time of three times two hours each day. Levels of alkaline phosphatase (ALP) and osteocalcin (OC) were compared after time intervals of four and seven days. mRNA expression of Collagen I, III and Cbfa1 was investigated after one, four, and seven days. ALP levels were significantly increased in the D+8 group after four and seven days (147.1+/-6.3%; p<0.05 and 168.6+/-6,5%; p<0.03) and in the D-8 group after 7 days (197.4+/-10.4; p<0.04). Cyclic strain had a significant influence on ALP-secretion (F=7.5; p<0.01). In the D-8 group there was a significant increase in OC secretion after 4 days (140.9+/-12.5%; p<0.05).; p<0.01). The effect of stretching was significantly stronger than that of dexamethasone (F=17.2 vs. 1.8). Collagen I (Col I) expression was upregulated in D+8 cultures after 4 days (215.0+/-53.3 p<0.04) and after seven days (166.7+/-55.7; p<0.04). Collagen III (Col III) expression was upregulated in D+2 and D+8 cultures after 4 days (200.7+/-16.3 and 185.9+/-12.7; p<0.04) and after seven days (154.4+/-10.1 and 118.8+/-16.4; p<0.04). There was a significant increase of Cbfa1 expression in D+8 cultures at all investigated time intervals (day 1: 105.5+/-3.7%; day 4: 104.7+/-3.0%; day 7: 104.4+/-2.1%; p<0.03). Stretching (F=20.0; p<0.01) was a stronger contributor to Cbfa-1 expression than dexamethasone (F=12.1; p<0.01). Cyclical mechanical stimulation with 8% elongation increases ALP and OC levels and upregulates Col I and III synthesis and Cbfa1 expression. In the short term, cyclical stretching is a stronger differentiation factor than dexamethasone. Cyclical stretching and dexamethasone both enhance the osteogenic commitment of hBMSC.

Adult↗
PubMed2004

[Principles of callus distraction].

Callus distraction is based on the principle of regenerating bone by continuous distraction of proliferating callus tissue. It has become the standard treatment of significant leg shortening and large bone defects. Due to many problems and complications, exact preoperative planning, operative technique and careful postoperative follow-up are essential. External fixators can be used for all indications of callus distraction. However, due to pin tract infections, pain and loss of mobility caused by soft tissue transfixation, fixators are applied in patients with open growth plates, simultaneous lengthening with continuous deformity corrections, and increased risk of infection. Distraction over an intramedullary nail allows removal of the external fixator at the end of distraction before callus consolidation (monorail method). The intramedullary nail protects newly formed callus tissue and reduces the risk of axial deviation and refractures. Recently developed, fully intramedullary lengthening devices eliminate fixator-associated complications and accelerate return to normal daily activities. This review describes principles of callus distraction, potential complications and their management.

Bony Callus↗
PubMed2004

[Knee para-articular focal dome osteotomy].

Focal dome osteotomy (FDO) is a cylindrically shaped osteotomy, with corresponding bone cuts rotating around the central axis of the deformity. Thus, complete correction can be achieved without secondary translation. FDO provides high adjustability of the bone ends, optimal bone contact, and high primary stability. As with straight cut closing, neutral, and opening-wedge osteotomies, FDO allows closing, neutral, and opening corrections. Opening FDO allows preservation of bone contact, whereas closing FDO does not require removal of bone stock. The osteotomy can be modified to tighten the medial collateral ligament. A FDO below the tuberosity does not compromise patellofemoral function and reduces the risk of intra-articular fractures. Sufficient bone stock of the proximal tibial or distal femoral fragment allows intramedullary stabilization. FDO is of high value in the treatment of sagittal plane and frontal plane corrections of the knee even in severe deformities.

Bone Malalignment↗
PubMed2003

[10-year results of bone marrow stimulating therapy in the treatment of osteochondritis dissecans of the talus].

The optimal operative therapy for the treatment of osteochondritis dissecans tali is still controversial. Beside bone marrow-stimulating techniques like abrasion arthroplasty, drilling and microfracturing, new techniques like autologous osteochondral transplantation and autologous chondrocyte transplantation are increasingly used. This study reviewed the clinical, radiological and subjective long-term outcome of bone marrow-stimulating therapy for 45 ankles with an osteochondritis dissecans tali stage 3 or 4 according to the classification by Berndt and Harty. All ankles were treated by the removal of the dissecate and abrasion of the subchondral bone. In 67%, an additional antegrade drilling of the defect was performed. The average maximum size of the lesion was 1.1 cm. At follow-up examination, 10.4 years (7.1-13.5 years) postoperatively, the average AOFAS-score was 91 points (66-100 points). Using the score of Mazur, the outcome of 28 ankles (62%) was rated excellent, 12 ankles (27%) were rated good and five ankles (11%) fair or poor. Progressive osteoarthritic changes, according to the classification of van Dijk, were seen in seven ankles (16%). Reoperations were necessary in eight cases (18%). Obesity, age older than 40 years and preoperative osteoarthritic changes had a significant negative impact on the clinical outcome. Bone marrow stimulating therapy is an inexpensive, low invasive therapy and a good therapeutic option at least for small Berndt/Harty stage 3 and 4 ODT lesions. Autologous chondrocyte transplantation and osteochondral autografts yield encouraging 2- and 4-year results, but still have to prove their superiority in long-term follow-up studies.

Adolescent↗
PubMed2003

[The prosthesis nail -- a new stable fixation device for periprosthetic fractures and critical fractures of the proximal femur].

Increasing numbers of total hip arthroplasties in combination with increasing age and growing daily activities of the elderly lead to increasing numbers of periprosthetic fractures and revision arthroplasties in osteoporotic bone. The prosthesis nail is a hybrid of a hip prosthesis and an intramedullary nail allowing immediate full weight bearing and early rehabilitation. The prosthesis nail consists of three self-locking components: a distally locked intramedullary nail, different lengthening modules, and a hip prosthesis module. From 1992 to 1999, 28 prosthesis nails were implanted in 26 patients (40-88 years, mean age: 71 years). The indications were 21 peri- and subprosthetic fractures caused by trauma, 2 fractures of the proximal femur in combination with a fracture of the femoral head or severe degenerative arthritis, and 4 revision arthroplasties associated with poor bone quality. A combination of the prosthesis nail and bone cement was used in one patient suffering from a pathological fracture of the distal femur. Patients were additionally treated with wire cerclage (six patients) and autogenous bone grafting (ten patients). All patients-except those who received a reconstruction of the acetabulum in the same session (four patients)-were mobilized with full weight bearing on the operated side as soon as wound pain diminished. Bone healing was observed in all periprosthetic fractures. In three patients the prosthesis nail had to be revised: one patient suffered from recurrent dislocations and in one patient weighing 350 pounds limb shortening occurred after the distal locking screw broke. Intramedullary infection was observed once after treatment of a periprosthetic fracture. When bone union was achieved the prosthesis nail was removed and the patient was mobilized with a girdlestone situation. The idea of the prosthesis nail is based on the logical consequence of treating femur fractures with the most efficient procedure, which is intramedullary nailing. The prosthesis nail can be applied according to the requirements of the fracture as a reamed or unreamed nail and immediate full weight bearing is possible. Considering the high average age of the patients, low morbidity, short rehabilitation time, and low costs are the major advantages of this new device. Taking into account the unfavorable preoperative conditions associated with elderly and multimorbid patients, the rate of complications is relatively low.

Acetabulum↗
PubMed2001

Alteration of fracture stability influences chondrogenesis, osteogenesis and immigration of macrophages.

Mechanical conditions at the fracture line determine the mode of fracture healing (osteonal versus non-osteonal bone union). The aim of this study was to investigate the influence of differing degrees of fracture stability on the time course of chondrogenesis, enchondral ossification and immigration of macrophages into the fracture callus. Using a fracture model of the rat's tibia, histological (Azan staining), immunohistological (antibodies directed against the macrophage-specific surface antigen ED2), and molecular biological techniques (expression of the mRNA of the cartilage-specific collagen IX, osteocalcin - a marker for mature osteoblasts - and the macrophage-specific macrosialin) were employed. In terms of histology and molecular biology (collagen IX mRNA expression) chondrogenesis in the fracture gap continued for longer in less stable fractures. In more stable fractures bone formation - identified by osteocalcin mRNA expression - increased from day 12 onwards. The expression of the macrophage-specific surface antigen ED2 and the mRNA of macrosialin was more pronounced but of shorter duration in the more stable fractures. This study shows that differing degrees of fracture stability not only influence the interplay between osteogenesis and chondrogenesis but also alter the kinetics of macrophage immigration into the fracture callus. These findings could aid in better understanding the cytobiologic mechanisms of callus formation and may suggest that macrophages are an important factor not only in soft tissue healing but also in bone healing.

Animals↗