Norbert Haas

Hamstring Tendon Versus Patellar Tendon Anterior Cruciate Ligament Reconstruction Using Biodegradable Interference Fit Fixation A Prospective Matched-Group Analysis

Background There are still controversies about graft selection for primary anterior cruciate ligament reconstruction, especially with respect to knee stability and functional outcome. Hypothesis Biodegradable interference screw fixation of hamstring tendon grafts provides clinical results similar to those achieved with identical fixation of bone-patellar tendon-bone grafts. Study Design Cohort study; Level of evidence, 2. Methods In 1996 and 1997, primary isolated anterior cruciate ligament reconstruction using a bone-patellar tendon-bone autograft was performed in 72 patients. Since 1998, hamstring tendons were used as routine grafts. Matched patients with a hamstring tendon graft were selected from a database (n = 284). All patients were followed prospectively for a minimum of 2 years with KT-1000 arthrometer testing, International Knee Documentation Committee score, and Lysholm score. Results In the bone-patellar tendon-bone group, 9 patients were excluded because of bilateral rupture of the anterior cruciate ligament, 3 patients (4.2%) had a graft rupture, and 4 patients were lost to follow-up (follow-up rate, 92.1%), leaving 56 patients for a matched-group analysis. In the hamstring tendon database, the graft rupture rate was 5.6% (P = .698). The Lysholm score was 89.7 in the patellar tendon group and 94 in the hamstring tendon group (P = .003). The KT-1000 arthrometer side-to-side difference was 2.6 mm for the patellar tendon group and 2.1 mm for the hamstring tendon group (P = .041). There were significantly less positive pivot-shift test results in the hamstring tendon group (P = .005), and hamstring tendon patients showed lower thigh atrophy (P = .024) and patellofemoral crepitus (P = .003). Overall International Knee Documentation Committee scores were better (P = .001) in the hamstring tendon group (hamstring tendon: 34 × A, 21 × B, 0 × C, 0 × D; bone-patellar tendon-bone: 17 × A, 32 × B, 6 × C, 0 × D). Conclusions In this comparison of anterior cruciate ligament reconstruction with bone-patellar tendon-bone and anatomical hamstring tendon grafts, the hamstring tendon graft was superior in knee stability and function. These findings are partially contrary to previous studies and might be attributable to the use of an anatomical joint line fixation for hamstring tendon grafts. Thus, hamstring tendons are the authors’ primary graft choice for anterior cruciate ligament reconstruction, even in high-level athletes.

Patterns of cell death: the significance of apoptosis for dermatology.

Abstract Development, function, remodelling, and senescence of multicellular organisms depend on the coordinated occurrence of physiological, actively induced cell death in two major patterns: terminal differentiation and programmed cell death (apoptosis). Apoptosis is a highly selective form of “cell suicide” with characteristic morphological and biochemical features: chromatin condensation, formation of apoptotic bodies, and DNA fragmentation by activation of endonucleases. Here, we outline the current understanding of apoptosis and its subtypes, discuss their biological functions, and delineate why apoptosis is relevant to the skin and its diseases. We distinguish apoptosis from necrosis, and discuss the regulation of apoptosis by selected genes, hormones, growth factors and cytokines. The epidermis and the regressing hair follicle offer interesting models for studying the as yet ill‐understood biology of epithelial cell apoptosis. The selective manipulation of cell death programs may become part of the therapeutic arsenal of clinical dermatology.

Expression of stem cell factor in cutaneous mastocytosis

Stem cell factor has recently been identified as a potent growth factor for bone marrow stem cells, melanocytes and mast cells. In order to evaluate its possible role in human mastocytosis, skin lesions from 13 patients with urticaria pigmentosa and five patients with mastocytomas, and normal skin specimens from five healthy donors were studied by immunohistochemistry, using polyclonal and monoclonal (hkl‐12) antibodies against stem cell factor, and a monoclonal antibody (YB5.B8) against its receptor, the c‐kit proto‐oncogene product. Stem cell factor expression was noted in all sections studied, with an equal distribution pattern for both antibodies, but a weaker intensity with the hkl‐12 reagent. Cytoplasmic staining was noted in keratinocytes, Langerhans cells, sweat gland ductal lining cells, mast cells, endothelial cells and spindle‐shaped dermal stromal cells. An intense, diffusely granular reaction pattern was noted in all cells, except for a sparse, coarsely granular pattern in mast cells and stromal cells. In urticaria pigmentosa, staining was weaker in keratinocytes, but more prominent in Langerhans cells. In all sections, toluidine blue‐positive mast cells and TA 99‐positive basal epidermal melanocytes were the only cells to react with the c‐kit antibody. Mastocytomas and urticaria pigmentosa lesions thus exhibit different patterns of stem cell factor expression. However, a possible pathogenetic role of this factor in mastocytosis remains to be determined.

The incidence of osteitis in open fractures: an analysis of 948 open fractures (a review of the Hannover experience).

Summary: Even though treatment protocols of open fractures have been improved in the past two decades, osteitis is still a major complication in these injuries. To investigate the primary factors responsible for posttraumatic osteitis, 19 cases of osteitis out of 297 open fractures (retrospective series from 1981 to 1983) and nine cases of osteitis out of 651 open fractures (prospective series from 1984 to 1989) were analyzed. The Hannover fracture scale was used for quantitative evaluation of the injury. A high prognostic index for bone infections was found for the amount of bone loss, the fracture type, the type of bacteriologic contamination, deep soft-tissue defects, compartment syndromes, vascular injuries, and soft-tissue infections.

Phenotypic evaluation of cultured human mast and basophilic cells and of normal human skin mast cells

In order to evaluate various markers for human mast cells, two human mast/basophilic cell lines (HMC-1/KU812), cultured mast cells from the peripheral blood monocytic fraction and peripheral blood monocytes were compared with mast cells in tissue sections from normal skin, using histochemistry, enzyme histochemistry and immunohistochemistry. All reagents stained normal skin mast cells, with toluidine blue, tryptase reactivity and antibodies against the FcεRI and the stem cell factor receptor (c-kit) being most active. The cell lines and mast cells cultured from peripheral blood were negative for avidin, safranin and chymase, strongly positive for c-kit and variably reactive with all other reagents. All antibodies except AA1 against tryptase also stained one or several epidermal and dermal cell types or blood monocytes. Histochemical stains (toluidine blue, avidin) and reagents for the enzymes tryptase and chymase are thus specific markers for mast cells. The frequent reactivity of antibodies against mast cells with other cell types indicates interesting functional and ontogenetic relationships between these cells.

Expression of the c-kit receptor in hypomelanosis: a comparative study between piebaldism, naevus depigmentosus and vitiligo

In order to investigate possible alterations in c‐kit protein expression on epidermal melanocytes in different hypopigmentary disorders, we have examined skin specimens from one patient with piebaldism, one patient with naevus depigmentosus, and five patients with vitiligo. Cryosections were examined by immunohistochemistry using monoclonal antibodies against the c‐kit protein (YB5.B8) and melanosomes (TA99).

Demonstration of the high‐affinity IgE receptor on human Langerhans cells in normal and diseased skin

Summary Epidermal dendritic cells of normal adult foreskin, and of lesional skin from patients with atopic eczema, stasis eczema and urticaria pigmentosa are shown to be highly reactive with two different monoclonal antibodies (29C6 and 6F7) specific for extracellular domains of the α‐chain of the high‐affinity IgE receptor. By their distribution pattern, the reactive cells are Langerhans cells. This is confirmed by immunoelectron microscopic demonstration of Birbeck granules in the labelled epidermal cells. Very weak staining is observed on the same cells with an antibody (TÜl) against the low‐affinity IgE receptor. Pre‐incubation of the sections with IgE partially blocks binding of 6F7 antibody. Langerhans cells, together with dermal mast cells, can therefore bind IgE with high efficiency, and may in this way participate in IgE‐mediated cutaneous diseases.

Treatment of Complex Acetabular Fractures Through a Modified Extended Iliofemoral Approach

Objectives To assess the rate of anatomic reconstructions as well as approach-related morbidity and complications in the treatment of complex acetabular fractures through a modified extended iliofemoral approach. Design Prospective clinical study. Setting Level I trauma center, University Hospital. Patients Inclusion criteria were as follows: (a) associated acetabular fracture or transverse fracture with comminuted roof area stated as not sufficiently reconstructable through a single approach, and (b) age between sixteen and sixty-five years. A total of forty-nine patients with fifty complex acetabular fractures could be included out of the series of ninety-six acetabular fractures treated operatively from August 1992 to February 1996. Open reduction and internal fixation of complex acetabular fractures through the modified extended iliofemoral approach were performed. Results In 80 percent of the fifty fractures the reduction was anatomic with a remaining displacement of less than or equal to one millimeter, in eight cases there was a persistent displacement of two millimeters, and two fractures had a poor result with a three-millimeter displacement. Complications included 8 percent loss of reduction, 13 percent heterotopic ossification grade 3, and 4 percent avascular femoral head necrosis. At the two-year follow-up there were 74 percent good or excellent radiographic and clinical results. Two patients had already been reoperated with total hip replacement, and the two patients with femoral head necrosis are currently scheduled for arthroplasty. Conclusions The modified extended iliofemoral approach proved to be appropriate to achieve anatomic reduction in complex acetabular fractures. The high rate of approach-related morbidity has to be considered carefully and may lead to a decreased incidence of extended approaches.

Interleukin-6 expression in the skin of patients with lupus erythematosus

Abstract It has been proposed that interleukin‐6 may play a role in the pathogenesis of autoimmune diseases like lupus erythematosus. We have therefore investigated the immunoreactivity of IL‐6 in 32 skin biopsies of 23 patients suffering from chronic discoid lupus erythematosus (n=16), subacute cutaneous lupus erythematosus (n=5) and systemic lupus erythematosus (n = 5) as well as in uninvolved skin (n = 6) and in normal skin from healthy volunteers (n = 3). Increased immunohistochemical staining was detectable in 14 of 26 biopsies from lesional skin. The remaining biopsies from lesional, non‐lesional and normal skin displayed only minimal or no reactivity, but 8 out of 12 lupus erythematosus patients had been pretreated with local or systemic antiinflammatory drugs. Irrespective of the LE subtype, immunolabelling was generally most intense in the basal layer of the epidermis, with additional intense suprabasal staining in sections from 2 of 5 SLE patients. Preferential production of IL‐6 in the lower parts of the epidermis was confirmed by RNA in situ hybridization. No correlation was found between the deposition of immuno‐globulins and complement at the dermo‐epidermal junction and IL‐6 expression in keratinocytcs. These data suggest that IL‐6 may be involved in LE although its exact role in the pathogenesis of the disease needs to be further elucidated.

Comparative immunoreactivity of the eosinophil constituents MBP and ECP in different types of urticaria

In order to elucidate the role of eosinophil constituents in urticaria, we investigated major basic protein expression immunohistologically in comparison with that of eosinophilic cationic protein and the low-affinity IgE receptor in lesional and uninvolved skin of different types of urticaria. Eosinophil activation was studied with the markers EG1 and EG2. Different eosinophil constituents were found in all urticarial lesions except those of urticaria pigmentosa. MBP staining tended to be distributed diffusely throughout the tissue, whereas EG1 and EG2 antibodies were located at or close to individual cells. Staining with the low affinity IgE receptor antibody was rare. In uninvolved skin, major basic protein and particularly eosinophilic cationic protein reactivity was found in chronic recurrent urticaria, delayed pressure urticaria and, to a minor degree, in cholinergic urticaria. No correlation was found between antibody reactivity and eosinophil counts. Reactivity with either of the eosinophil constituents is thus a better marker for eosinophil involvement than routine H&E staining of the cells. The demonstration of eosinophil constituents in nonlesional skin of some urticaria patients suggests generalized eosinophil activation in certain subtypes of the disease.